I'm happy to see the fears about cross-border flights get hashed out in a public forum.

After my last flight well into the USA, I called Helena and Great Falls customs, to discuss what would have happened if I had landed out. They had both heard about the flight. ATC wasn't 100% convinced I was not going to land, and had called customs. Lesson learned - be totally clear in your flight plan.

I will make a note in OLC in the future that the overflight was legal.