That fits perfectly with the rule; that employment relationship arose in New Jersey.
Then maybe I misunderstood your correction. First you said
which my son’s situation absolutely fits. You then corrected it to
I’m not sure how my son being hired by a NY based employer and sent to work for a day in NJ is different from an employee of a temp agency based in NY being sent on a assignment to Connecticut or any employee of a company based in their home state (say an MLB batboy) being assigned to work out of state.
Can you explain what you mean by the state where the employment relationship arose?
He was hired for a specific job that was to be performed in New Jersey. It doesn’t matter where his employer was based. If you were an employee of Best Buy (based in Minnesota), and you worked at their store in Trenton, you wouldn’t pay Minnesota income taxes.
If I , as a NY resident were hired by Best Buy to work in a NYC store, I would pay NY income taxes, not Minnesota. But if I were then sent to work in the Trenton store, even temporarily , I would owe NJ non-resident tax if I met the filing threshold. And the same goes for the NY resident sent by a temp agency to work in NJ, as well as not only non NJ-resident professional athletes and actors but every other non NJ-resident who travels with the team or production. But when you said the general rule is
I understood you to be correcting your earlier statement to “Whether or not you have to file a return in a given state where income was earned depends on the state’s laws. The general rule is no for employees whose employment relationship arises out of a particular state - though for obvious reasons, enforcement is difficult if not impossible.” which I took to mean that NJ is an exception to the general rule, not that it fits the rule. If this sounds argumentative, I don’t mean it to, but I just don’t understand if you’re saying that most states require non-residents to file returns on income earned within the state if it meets the filing threshold or that most states don’t.