Then they would just prevent mid-deck entry.
Plus, single-deck and double-deck games are easily watched for shenanigans, because the count moves up and down so fast that it's easy to tell whether someone's varying the bet with the count or not.
At first I was going to say that you'd need more than the min-max spread to get an advantage (6:5 BJ requires a TC of +5 or +6 to be EV+, and in a shoe game, that happens less than 1% of the time, so you'd have to spread 1-100 which most tables won't accept), but upon researching at blackjackincolor, it looks like single-deck game you'll hit that TC about 5% of the time, so you only need about a 1-20 spread. So it's doable if someone will let you.
The point of the gorilla BP is to jump in for an extended time, at least 4-5 hands, not to hop in on one hand, leave, and then stand behind the table again. That looks so horrendously suspicious.