I did this at Circuit City way back.
They had a B2G1 on the Greatest Hits, but fucked up, and all $20 games became $5.
So I went down there, grabbed a ton of shit. A guy was watching me and said "Oh, so it's still working?" and I just said I was about to find out. I also brought along my roommate who grabbed a bunch, too.
We go to the checkout and the guy scanning me was loving these prices.
My roommate got stuck in a line behind a woman who refused to pay these prices, because it felt wrong to her, so they called a manger. I had finished my shit, but by the time my roommate was rung up, they were manually fixing the glitch.