Moving a used truck my dad is buying from Evansville to Northwest Indiana. My dad thinks I need to get transport plates(temporary registration) to make trip. Necessitating a trip to Bmv. I have always just used title and bill of sale. Never been stopped though.
There's a long discussion of a similar topic here. The upshot is that you either have to have a plate you are transferring to the vehicle (you have 31 days to do that) or if you have no plate to transfer, you have to get a temporary tag. That an officer may not cite you or have the vehicle towed if you don't have either, is a matter of his mercy, not the law.