I worked at Best Buy and Sears in the late 90’s. People tried to scam us every day.
Sears didn’t do any checks if anything. You just took your boxed up computer to the back of the store and you got your money back. It was common to pull the RAM and HD from a computer, return it for another, and then you had double the memory and drive space for free.
You couldn’t do that at Best Buy, the Tech bench (before they had the Geek Squad) would inspect your returns. If you wanted to fool us, you’d have to make it look like you never opened the boxes, and put the correct amount of patio bricks in it.
You couldn’t swap video cards or RAM, we checked the model numbers. So you’d have to take the video card over to the appliance department, slice the side of the box with a knife, remove the video card and throw the empty box in a washer or microwave. When the Voodoo 5 came out we found every single one was stolen and the boxes in a freezer that was on display.
We even had a RAM tester that would tell you the speed and size of the chips. We never got one that would do DIMMs, just SIMMs, so as the Pentium II became popular it was less useful.
Now, if you knew someone who worked at the tech bench, you could bring your home PC in for a bullshit service like a $29.99 disk defrag, and you could get it loaded up with memory, disk drives, or hell, you could just stick as many audio CD’s as you could in your tower. Just make sure the case screws are on tight when you leave, or the panel falls off along with whatever you were smuggling out, right in front of the whole store.
Lastly, there was a DEVO area towards the back of the store, basically a dumpster full of returns. I heard they got sold to the lowest bidder, stuff we couldn’t return to the manufacturer for some reason. Memory, hard drives, all kinds of random stuff would end up back there because the computer said so. Anything that could fit in a pocket, people helped themselves to.