Playing the devil’s advocate here. Is is fair that someone like me has to come in on Sunday to finish the work of someone that won’t work on Sunday? This is especially true of anyone working in a schedule driven occupation. If they don’t want to work on Sunday, go get a menial job at Hobby Lobby or Chick Fil A. Things like this is why I think the separation of church and state should be as wide as the Grand Canyon, not a pencil line on a piece of paper.
I found it a little odd that these would be your go-to examples of jobs that don’t require working on Sundays, especially when juxtaposed with the post directly above yours.
Not working on Sunday used to be the norm for most jobs, especially the non-“menial” ones, and still is to some extent, though not nearly as much as it used to be.
If the line separating church and state were as wide as you propose, it would disappear utterly. Maybe in the world you propose it wouldn’t be the government persecuting people on religious basis themselves, but the persecution would be just as real and just as inescapable. The only way to stop that is for government to be able to step in to stop private religious persecution.
Imagine a world where most businesses refuse to do business with non-Christians, and when non-Christians try to complain, the government just steps back and says “Nuh-uh, separation of church and state, not gonna touch that”.
Believe me, I get it. I’m in a 24/7/365 business. Anyone who insists their “religion” (whatever poppycock that is) overrides their obligation to work whenever, wherever, whyever is a non-starter who’s simply not hired. And rightly so.
But when I have to waive my rights to basics like overtime pay, protection by OSHA, etc., as a prerequisite to being hired, I, and tens of thousands of other people, are being screwed. Not in the name of religion or lack of same, but in the name of increased profit, pure and simple.

In General, you can not be required to sign away your rights, and more or less any such contract in null and void.
Unfortunately, in general most corporations have legal teams so powerful that you play hell finding someone to represent you and, even if you do, there will be craploads of pressure to take a settlement tied to a non-disclosure agreement.

Anyone who insists their “religion” (whatever poppycock that is) overrides their obligation to work whenever, wherever, whyever is a non-starter who’s simply not hired. And rightly so.
Again, right or wrong, if true, your company is in violation of the law. Even the lukewarm protection that exists under the current model (which the Supreme Court is being asked to, and probably will, strengthen), religious accommodations require slightly more than just a straight-up blacklisting of anyone who wants one.

I found it a little odd that these would be your go-to examples of jobs that don’t require working on Sundays, especially when juxtaposed with the post directly above yours.
I don’t understand what’s odd about those examples - those are perhaps the only two non-religious employers where you can be certain you will not be asked to work on Sunday.

the only two non-religious employers
They are far from non-religious.
Poor wording, I guess- they are the about the only employers other than actual religious institutions where you can be certain you will not be asked to work on Sundays.
Good answer.

Unfortunately, in general most corporations have legal teams so powerful that you play hell finding someone to represent you and, even if you do, there will be craploads of pressure to take a settlement tied to a non-disclosure agreement.
Yes, that can happen. But for example in CA if you signed away your right to overtime, but were NOT in an exempt position, the State will investigate- you will not need to hire a lawyer. Similar if you say you are not a real employee, just a contractor- the government will go after them.
But yeah, if it is something grey? Then you are likely up shit creek, unless a lot of other employees complain.

After pulling the pin, the grenade got caught on his wedding ring.
Neil Armstrong jumped from the back of a truck, caught his wedding band on something, and lost the finger. As a comedian at the time said, “That’s one small step for a man— Aughhh!”

But for example in CA if you signed away your right to overtime, but were NOT in an exempt position, the State will investigate- you will not need to hire a lawyer.
Will they investigate if only one person complains, or does there have to be a number of incidents before they can justify the expense of going against a corporation?

But what’s “reasonable”? who knows. I think trying to come up with a black and white rule is always going to leave someone feeling put-out.
What is reasonable is dependent upon the work environment, the company, the needs of the employee, and the resources of the employer. The requirements to make accommodations for religious beliefs aren’t as serious as they are for an American with Disabilities Act accommodation. For a religious accommodation, anything with more than a “de minimis” cost to the company can be enough of a reason not to grant the accommodation. If I have to hire another employee to work on Sunday, that’s more than a de minimis cost. It can get more complicated than that of course.

What I do think is unfair from the get-go is to start with the assumption that a religious accommodation must be considered more seriously than one that stems from a secular
personal position. I don’t believe that religion deserves to be elevated in that way.
Exercising your religion is a Constitutionally protected right while going to see a ball game isn’t. It might not be fair, but given our history, I think there’s a pretty good reason why one activity is protected and the other isn’t.

Everything I can find says they are entitled to to unpaid leave from private employers , although that’s of course subject to state laws , court decisions and possibly the details of the situation.
Under the Uniformed Services Employment and Reemployment Act, private employers don’t need to pay their employees leave while they’re on leave from the company for military duty. You can find a list of rights military personnel have here.

those are perhaps the only two non-religious employers where you can be certain you will not be asked to work on Sunday.
You just have to make sure you get out of work before Lumbergh catches you.
There are states laws allowing parents to take time off for children’s events.
Workers at locations with at least 25 employees must be allowed to take up to 40 hours off each year—up to eight hours per month—for school- or daycare-related activities. This type of leave can be used for a broad range of activities, including to:
Find or enroll a child in a school or licensed daycare program.
Attend a child’s a play, awards ceremony, sporting event, graduation or other activity.
California’s Working Parents Can Take School-Related Leave (shrm.org)

Will they investigate if only one person complains, or does there have to be a number of incidents before they can justify the expense of going against a corporation?
For the past few years, those two things i mentioned have been priorities.
So, as a business owner who interviews two applicants who are equally qualified, can I not hire the one wearing a cross, since they may require religious accommodations?
Nope. That’s explicitly illegal.

So, as a business owner who interviews two applicants who are equally qualified, can I not hire the one wearing a cross, since they may require religious accommodations?
Discrimination based on religion is spelled out quite clearly as being illegal.