We're here tonight with a quick public service announcement for those of you who have just started playing GTA Online and don't realize that if you talk into your mic to interact with the game, the other players in your game session will hear you. Yes, this means that if you are flirting with strippers, everyone else will hear what you say, as this older PSA demonstrates all too well.
Singing in the shower in GTA Online will also be heard by the rest of the server, as will shouting at shop owners to scare them. Basically, if you use your microphone, GTA Online doesn't differentiate who hears it based on context.
However, if you don't want everyone playing with you to hear what you have to say, you can change your microphone settings from the in-game menu and avoid this sort of embarrassment.