I've only been SF TM in my store for about a month so I'm not sure if this is a regular thing, but when I go to back up at register and it's calmed down and time for me to go, the GSA/LOD will turn my light off for me. Theu[They] then get in line behind the last person who walked up when the light is still on, and announce kindly to anyone that comes up after they arrive that the lane is closed. They usually don't get anyone walking up though, because they turn their back to me/the cashier and face any incoming customers. That usually gets the message across loud and clear.
I thought that was a pretty nice touch.
edit: To add that they also do this for cashiers who are scheduled for a break/meal or are about to be done with their shift.