there tends to be a spy who tells you not to throw in jail

In my experience town doesn't mind nl'ing when they still have a Jailer (this changes when town lacks one or the jail0r dies).

If there is no jailorino, then chances are you won't be able to cage anyone. Just try to get townread and play as a nilla in that scenario.

As in which setups favor his appearence.. idk. Setups with jailer probably make his life a little bit more interesting.