No, in both states I actually went and read their statutes and there is nothing stating nonresidents can carry OC. Michigan actually specifies "legal Michigan residents".
Rather than going by what others have done in the past I go by what is published for each specific state. Just because one has gotten away with OC'ing in another state does not mean it is legal for a nonresident to carry there and I will not inform someone it is legal to do so.
There is a huge difference between OC friendly to legal residents and OC friendly to nonresidents and until I either read the statute myself or someone shows me the exact statute that says its legal I will go with what is published.
You have said twice now it is acceptable and yet have not provided the statute in either case saying an Indiana LTCH can OC in either state.
That's not the way the law works. They don't pass laws to make things legal.
Have you seen anything that states that it ILLEGAL for a non-resident to OC? If not then you have to assume it's legal, the same as it would be for a resident.
I'll try to see if I can find anything that specifically states as much though (like va FAQ or some other semi-official document) but don't hold your breath.
You say it's illegal so the burden of proof is on you to show where it says that. It goes back to that ol' "you can't prove a negative" idea.