Or OK let's say they question the return and ask you to come to the "back office" .. never happened to me.. just get offended say no and walk out in a huff.
Btw. Never go to the back office unless police are asking you to. Very unlikely.
Most items don't have specific identifiers on them. The barcode is generic to the type of item not to the specific one in your possession. So they won't know which specific item of that type is being returned. It could be any one of them that they have sold. I returned something to Target once. Told them my spouse bought it for me so I had no receipt and they gave me a gift card in return for the amount of the item. The only store I personally know of that has a return code specific to the item you have in your possession is Macy's.
Not risky. Easy. As long as no serial or high theft item.. it's usually fairly simple. Worst they can say is no.