You don't like watching coach passengers walk through the First Class cabin? I do.

First Class passengers can bag-smack other people in just as easily as coach passengers. The large difference in seat count for the two cabins might be the reason you believe only coach passengers are capable of bag-smacking.

Besides, when 2L is used for boarding, you can't hear the announcements some people choose to make as soon as they enter the plane to their traveling companions "WE'RE IN SEAT 35A AND B!" or "ROW 28!!!".