GroupOn isn't all cut-price giant beanbags and cheap cocktails. Don't forget cupcake maker Rachel Brown getting swamped by thousands of unfullfillable orders, for example, or plenty of other small businesses who've felt the wrath of bargain-hungry people power.
The latest snaffu caused by a GroupOn stampede took place in York city centre over the weekend, where thousands flocked to sit on Santa's knee and marvel as his "magical train".
As it turned out, the show the shopping centre put on consisted of a simple marquee-and-santa-on-a-chair number, with no special extras to be seen - and no magical trains.
Cue hundreds of extremely disappointed children and some seriously angry parents... seriously angry parents who weren't afraid of screaming and swearing at the attraction's staff.
Eventually the abuse got so much that one of the elves involved quit on the spot. In other words: not a good day out for one and all.
But how did this blunder happen? It seems that there was a mistake at GroupOn HQ, where the description for another grotto in Hull - which did have a magical train, apparently - was used to advertise York's more modest endeavour.
“We have just got a little grotto in town, they made us out to be almost an Alton Towers experience,” explained Penny Ward, one of the organisers of the York grotto.
“Owing to a technical error, we apologise that the picture and wording used in this promotion may have indicated that a train ride was available at York Winter Wonderland when this wasn’t the case," said a GroupOn spokesperson. “We regret any disappointment this may have caused."