It's not indianas job to enforce laws for Wisconsin.....I think even if you got stopped it would be more of an inconvenience, finding out where you are from and sending you on your way....
I might be tempted to leave the camp-inn "plate" in place just to give the casual observer something to look at....because he doesn't necessarily know the vehicle is from a place that doesn't require plates, he could pull you over thinking you were from his own state.
Another thought would be to carry your states code showing plates aren't required....cops have been becoming increasingly totalitarian lately. As a ham radio operator, I am allowed to have radios in my car that a non amateur operator can't...a friend who customarily uses this privileges keeps the pertenant law taped in the battery compartment of his radios. He said it saved him a couple times.
Just $.02 worth.
