Sure, we could draw the line at allowing law enforcement to kidnap a suspect's family, but should we? To the contrary, I think we've given our employees in law enforcement entirely too much leeway already.
Not necessarily, but when you have a guy who's hiring fake hitmen to punish sellers trying to rip off buyers it's hard to argue that he never would have considered a hitman if not for law enforcement intervention.
The practice of law enforcement officers inducing a person to commit a crime he otherwise would not likely have committed. I have a hard time seeing why my extreme example couldn't be found to be entrapment if any law enforcement official were foolhardy enough to try it.