It would make me VERY suspicious.
As it has never been reported as happening, well not something I would be worried about.
I had to go into the localish Courthouse, now I needed to go to the Clerks office but still had to go through very impressive security for reasons that escape me, not TSA fully armed Sheriff Deputies who looked ex Green Beret, they had no interest in the paperwork, why would they?
Now I have heard of Cocaine soaked paper products but how much does this envelope weigh?