When I worked as the manager of a bowls' club bar, I'd sometimes put the prices up when special events were taking place.
I was serving in a local pub though, one Sunday lunchtime, when one of the two 'step-brothers' who ran the place (who were almost certainly actually a gay couple who simply weren't ready to 'come out') noticed what I'd charged for a round and got absolutely furious.
"How the hell do you expect us to make a profit if you can't charge the right prices?", he demanded to know.
I pointed out that I'd charged exactly the right amount, based upon the prices shown on the shelf edges and on the back of the pumps. A few minutes later he returned with a roll of sticky labels, together with a marker pen, and proceeded to increase all the prices by at least 20%.
So we had customers coming up to the bar to buy their second round who were somewhat less than impressed to find that it was going to cost them far more their first one did.
A short while later though the other 'step-brother' walked behind the bar and demanded to know where all of the new price labels had come from. When I told him that his step-brother had just increased all of the pub's prices dramatically , he told me exactly what he thought of him and then went round removing all of the stickers.
So customers who came up to the bar for their third round then found that the price had dropped down to the same as it was for their first round!
All in all, it was a very strange way to run a pub in my opinion!