I used to live by a rest stop many, many years ago in Ohio (before the internet) and was fortunate enough that it glory hole. So I would stick to cruising the restroom. The old foot shuffle and finger in the hole was usually enough to get an interested party to stick their dick through the hole. (Though ended up going back to the truck with few of the men I met from the restroom.)
I just always figured if the shades were closed they were sleeping, I'd walk around the trucks at times, but then head to the restroom. I always figured if they saw me go in, they'd get the idea lol.
The funny thing about that hole looking back, was it would get covered with steel plates and by the next day it would be ripped off lol. Always pictured someone going in with a full tool set to make sure tat glory stayed open!