So cameras only detect you when they're pointed in your general direction and you're close enough, right?
But if you use anything with a red cursor (thus implying something criminal or something that people nearby wouldn't want you to do) the camera either immediately breaks your stealth or starts combat with you- regardless of facing or even if there's anyone watching you do something.
[I'd realized this one ages ago, but it only just now occurred to me to submit this obvious bug]