Perhaps not a "turn off," but if a girl gets flirted with/asked out/complimented by men often, does it make her seem intimidating and unapproachable to other guys? Guys, if you personally know a girl like this, would you welcome the competition or be afraid to make a move?
For most guys its a turn on. Men are proud to have a "trophy girl", a woman who is highly valuable to other men. Now if he thinks he can't measure up to the competition and has confidence issues, he might just not pursue her but it's still not a bad thing. guys hit on girls who are hot so how could that be a turn off? If a girl rarely ever got attention then that'd mean she was ugly and what guy wants that?