For a game like poker, yes, but there is no value in keeping your cards secret in blackjack. Indeed, training/casual tables are often played with all player cards face up, and it doesn't change the odds at all.
I imagine banning cellphones at tables is mostly a blanket rule, so the pit staff don't have to use extra determination of whether it would be easy for the player to cheat.
cheating with a cell phone is a concern. however, cell phones at the tables are also a detraction from the game and are often a nuisance to others at the table. the house wants you playing the game, not talking on the phone.
communication devices are not the most affective cheating tools at house-vs.-player games unless you are communicating with the dealer or other house employee. i am not aware of any table games where other players are not allowed to see your cards. the dealer even steps in to help in most cases. a small advantage can be had in poker-like games where the players can conclude what the dealer doesn't have by looking at the cards already dealt to the players. however, i have not come across any place locally that enforces a rule along these lines.
what is confusing is when in the poker room where you are put up against other players and not the house, cell phones are allowed, at least in some places.
A felony for using an iPhone app? Ulp!
I thought they just ask you to leave.
in this case, the phone acts as a device that can give the player an elevated advantage. if you are just talking on the phone, they just ask you to step away from the table till you finish. if you are using it to cheat, then you are arrested.
