Our store does the training mode stuff, which usually draws a string of people walking by and asking "Are you open?" even though we block the aisles off (and they are usually at the end of the registers).....then we tend to let them watch for a while, then throw them on a register next to us and tell them to yell if they need help.....
2 funny things I can remember -
1) One girl had started training with someone else, but after the first hour or so, she was reassigned to me....she was great, and picked things up very quickly....she was on her own lane before long.......except that both of us who had trained her neglected to mention where we store the bags under the register, and one of the other trainers said she looked over and the poor girl was sitting there stealing a single bag at a time from the lane next over.....oops.....
2) I always have the pleasure of trying to train on shorthanded weeknights.....I had a very nice young man with me one day, and it was busy, especially for a midweek night, and even trying to swap so he could ring while I was watching for a few minutes was proving to be difficult....so our GSTL came over, grabbed him and stuck him on the register next to mine....and the first guest he got was the woman with an overloaded cart of items, every one of them on clearance, and nothing ringing up at the price that was marked.....even with 2 of us helping him, it took over 45 minutes to get this woman happy (it didn't help she was switching stickers on the product, which we pointed out to her that the clearance stickers and the produict description did not match).....I took him on break, and told him to please not think that he would run into this often, if at all, and that he just won the lottery of goofballs on his first try.....fortunately, he has blossomed since that, and is a big part of our store.....