Damaged USAAF aircrews heading to Switzerland

[Pathfinder]

I've read quite a few accounts of crews having battle and heading for neutral Switzerland, but have always wondered about the following: (of course, much of my thinking is speculation)

1) Why do you think there were reports of the Swiss using A/A fire against USAAF ships posing no threat?
2) A bigger question is why there were reports of them being attacked by Swiss fighters when making for Swiss airfields? I know this happened from crew reports.
3) I'm assuming that Swiss authorities informed the Red Cross who then informed the fighter/bomb groups where their crews had ended up?

If anyone can add factual or educated guesses for the above, please do share your thoughts.

Cheers