Someone who does it in Atlantic City cannot be asked to leave, but it can be rendered ineffective by frequent shuffling.  
Arnold Snyder devised the zen version of it and Ken Uston invented an "advanced point" kind. Among the first to do it was Edward Thorp, and other practitioners include J. P. Massar, who backed several teams who did it, and Jeff Ma, the subject of Ben Mezrich's tell-all. Someone who does it in Atlantic City cannot be asked to leave, but it can be rendered ineffective by frequent shuffling.  Usually assigning negative point values to tens and aces, this is, FTP, what technique practiced by MIT students playing blackjack in the movie 21?
Arnold Snyder devised the zen version of it and Ken Uston invented an "advanced point" kind.
{counting cards} at blackjack