This happened to my partner's mother. She works for a supermarket chain in the UK. I won't say which one, let's just say “this isn't just any supermarket”.
All the front line staff were gathered together one morning before opening and shown a video message from one of the higher ups say that because everyone had been doing such a great job they would be receiving a bonus. Later on the was told by the stores assistant manager that the message was meant for the management team only, not the front line staff (i.e. the people who actually do all the work).
But because they had all seen it they were told the company would have to honour it and give them all a bonus.
As it's a slightly more high end supermarket a lot of people I have met assume that they take good care of their workers but this is yet another example of how poorly they treat them.