Yep it works but not always. Try the old staring at the back of someone you don't know, they will eventually turn and look as if they know someone is staring. I might be wrong however
Do you remember the times it hasn't worked when you've tried it?
If it works all the time 100% then you'll make a fortune :p
I'm usually skeptical about stuff like this... I have no clue how Derren Brown did it, I'm sure it wasn't power of the mind, while I don't think it was an actor either.
Oh yeh.. Why were you sending BAD thoughts to them lol?