I had to do this once. One of my local charity shops has a area for 'designer' stuff that's more expensive. They had a bustier crop top for 40. It was a dupe for an actual designer, but very, very badly made. I told one of the staff, who sniffed at me and got the manager. First thing I said was I wasn't buying it cos it was too small, but they might get complaints for selling knockoff for designer prices. He looked at his, then called over the original woman and pointed out the lack of label on the inside, and the fact that half the stitching was doubled up and loose. Was on another rail for 5 the next day.