I assume the joke is (usually undocumented) people look for work in the parking lots of Home Depots, hoping to be hired for day labor, and the same may happen with the nerd glut in our culture and Best Buys.
I’ve never witnessed this as I live in a smaller city in Northern MN but it’s a cliche here in the States.
Ah, right, Best Buy was the Geek Squad. That’s who would be hanging out there.