Dealers call bosses to a table to observe plays that are out of the ordinary or involve something that might lead to a dispute. An example of the former is a player doubling down on a 12, while the latter could be a cash wager (you've heard dealers call out "money plays"). In both cases, the bosses are being alerted so they can monitor the play if they choose.
That's what's happening at Mount Airy. Surrender isn't a common rule, so the bosses want to monitor how the dealers handle it in live action. Additionally, a knowledgeable boss may keep mental notes on players who know enough to use the option, but that consideration is secondary at best.
Surrender allows you to end a hand for half a bet after seeing only your first two cards. For example, if you bet $20 and get 16 against a dealer ten, you can surrender and the dealer will take $10 (returning $10 to you). For the Pennsylvania game, and most others, basic strategy tells us to surrender 15 against a dealer ten, and to surrender 16 (except a pair of 8s) against a dealer 9, ten, or ace. That's all.
