They used to require players to put their two cards on a transparent spot of the table so that a camera below could id them for the television feed. RFID is much more secure than this, and it also reduces the times when cards can't be read because the player doesn't play them right.
Putting the cards past a reader or scanner while dealing would alter the flow of the game, and would also introduce other attack vectors.
Putting the cards past a reader or scanner while dealing would alter the flow of the game, and would also introduce other attack vectors.