Casinos now use training and technology to differentiate surprise vs. expected wins. It also becomes fairly obvious to spot once one knows the trick. To obfuscate the technique, some players are called to average tables. As a result, the players don't know whether their table is hot at the time. The overall win percentage is lower, resulting in lower ROI, but it's much more effective.
I assume it's not illegal to count, even if you are alone and use an obvious tactic such as playing $10 for dozens of hands, and play max bets only near the bottom of the shoe?
(Card counting done slightly wrong loses you more money in black jack faster than just following the table of optimal play.)
This way it doesn't look suspicious as no one altered their behavior (one early method to detect card counters was to observer changes in bet sizings as the count changes).
Honestly, many blackjack players that I see at the $5/10 tables are playing so badly that the casino wouldn't want them to have to wait for the shuffle to start getting their gamble on.