lets be fair though, unless you're extracting someone who's really really up to date on kidnapping techniques and procedures, when the tranq dart hits them, their first reaction is gonna be "ow! what the fuck?"
By the time they've had a look at the dart and figured out what's going on, it'll be sleepy sleepy time.
Who would realistically feel what could easily be a nasty insect bite and immediately call a swat team in?