A few weeks ago Playtech introduced the option to sit/play behind a player at blackjack tables.
Attachment 1877 Attachment 1878
As a behind seat player your decisions available depend on what the main player chooses to do e.g you can only double or split if the main player does so.
You also have the option to put your faith in the main player and double your bet.
Attachment 1879 ... follow main player.