The problem I have with Sonic is that they don’t even give me a way for me to tip the carhop. I very very rarely have any kind of cash on me at all, and they took the tipping option off of the credit card slips. I used to tip at least some when I went there, but I can’t anymore because I never have any cash or coinage on me. But to get to the point some people are making, all Sonic really is, is a drive through where you park. It was quite the thing when they first came out, and I’m sure some people still like sitting in their car and eating, but the vast majority of people I know order their food and leave to go home, or to a park or something. If they had an option to order at a window and “drive-through” then I’d do that. And that by itself isn’t really deserving of a tip.
And to point out to people about the minimum wage thing, everyone gets paid at least minimum wage. No exceptions, never. Even if a waitress gets $2.50 an hour plus tips, if she records no tips for a night, or very little tips, then her paycheck is automatically corrected to pay at least the minimum wage. Sometimes you make $15/hr, sometimes you make $5/hr. Just part of the job.
I think it depends on what you’re doing there. If you eat at the restaurant then I think you ought to tip, assuming there’s some ongoing interaction with the carhop (I’m not sure how this works, I’ve never stayed at a Sonic and eaten).
However, if you just buy your food and drive away, I don’t see any need to tip. In that situation, I don’t see any difference between Sonic and a McDonald’s drive-through, except that someone walks 20 feet to give you your food.
There have been times at McDonald’s drivethrough that they told me to park and they would bring my food out, so as not to hold up the rest of the line of cars. I would not tip for that.
The two girls that I know (classmates with my kids) that work at Sonic do not expect a tip. Which is not to say that they’re not appreciated. This probably varies from region to region.
What about places like Pick up Stix, where you order at the counter and get your own drinks, but they bring the food to the table? I generally don’t tip if it’s just me, but I have if I was with the kids and we ordered a lot and they left a bit of a mess.