Everything in the dumpster is property of the store until the trashman picks it up and dumps it into his truck. I had a slightly different problem when I worked for Joann's (Fabricland)...we had to do a walk around the store to check the locks, and that all the tables were folded, ready for the next day. I was supposed to have a different clerk do it every night...well, I always went behind them and checked the doors myself...would find upholstery fabric, nails, tools, thread, all kinds of trims ...all laid out at the back door...sometimes already stashed behind the dumpster. We had two girls who were related...their hubbys were in the auto upholstery business...and these two girls were supplying the goods. I told the manager ...she said thanks, and didn't say anything to the girls...another employee said the manager knew, but liked the girls...and that they had good sales. Sheesh! Needless to say...when I was working and we had to send someone home...it was always one or both of these girls. Told the manager to work them on her shift, not mine.
Back to the disposal of good items...happens in all stores...it's crazy...don't know how many times we gave Lowes & other stores destroy authorization, only to have a customer call the next week for parts...we would ask if the box was taped or had a mark on it...yep it had a number (the destroy authorization number)...the stores resold the items and told customers to call for parts.
You just can't win...no matter if you are the store or the supplier...that's why prices are so high in this country.