With diligent tracking of the ratio of face cards to nonface cards played and the number of cards left in the shoe one can gain a very slight edge at Blackjack. It's grueling but possible, I lived off Blackjack winnings until the actual work of it wore me down.
While that is true anon is fucking retarded and they don’t kick you out for counting cards mentally, only if you are using a device to assist you.
Edit: everyone downvoting me and responding really believes what they show in movies huh?
No, there are professional card counters that the casinos are aware of that they let play even knowing they are counting cards because it attracts other people to the table. As long as they are not raking in tens of thousands of dollars in a single night they do not kick out card counters.
Source - I worked at a fucking casino in Vegas you inbreds.
Uhhh... yes they do. The people watching the cameras all count cards so they know when you're doing it. If they see you betting along with the count they will ask you to leave.
How is it allowed? It's their casino. They're there to make money off you, which is why everything stacks in their favor and any games involving any actual skill are hobbled severely and using any gets you banned.
Now if you ask "how are casinos allowed" I'll ask right along with you. They are immoral and predatory - not literal fraud but it gets close, and either way it's treating people with addiction as cash cows.
If you're smart enough to count cards, you're smart enough to look up local laws and you're smart enough to know what games are rigged against your favour.
Not even remotely true. Smart people can be incredibly dumb.
Generally speaking, a blackjack table will run with 5-10 decks in the shoe. So counting isn't as effective, because the odds are diluted by volume.
Also, folks will often use aids to count cards, because keeping track in your head is difficult. What most people get thrown out for are carrying these aids.
This here is the answer. Unless you're scouting a table for a long while, you generally won't know how many in the shoe. That, mixed with the fact that mentally keeping track of 250-500 individual cards, not only is near impossible without an aid; you would also only have so many opportunities to "know" what cards are left. Thus, the 30 cameras pointed at you and identifying that you've been playing the same table for hours, they're going to know.
In reality, the casino industries current weak point is their electronics, specifically the slots. The software running on those things has been proven to be about as vulnerable as a payphone, and people have been caught running schemes on them.