I really like this idea for first time players. Gives them permission to take back a punishing mistake, but doesn't make it unlimited. Perhaps a nice way to generally balance any board game between newer and experienced players.
Watch It Played
Along those same lines, when I taught my students go, I would give them three “I’m in danger” tokens. Every time they made a move that would cost them the game or a lot of points, I would undo the move and take away a token.