I did my shopping, queued up and paid, thinking it was a bit much. Got to the doorway and checked receipt to see I'd been charged for one item three times.
So I turned round and went to wait beside the person who was now being served by the checkout person who'd served me. Someone made a snippy comment about "the usual practice is to queue". So I politely pointed out that I had queued and I was now coming back to rectify a mistake and wanted to ensure I was served by the same person rather than just been randomly allocated whichever assistant was free when it was my turn. They were still huffy, but could see that I wasn't buying anything. Should I have gone and queued again?
It never crossed my mind to to be honest, and I wouldn't have minded someone else doing the same.