I've seen this sort of things in videos of police encounters, too. "I suggest you do X" or "would you mind doing X" is some officers' way of being polite, but it leads to dangerous misunderstandings. When people say no, taking the statement literally, cops see them as trying to start a fight.

I'd love to see law enforcement trained in using basic, declarative sentences: "Sir, regulation X.Y.Z says you have to take your shoes off. Please step aside, do so, and rejoin the line."