About 20 years ago, I worked with someone that took advantage of absolutely everything they could under HR policies.If you are sick, take sick leave. If you need special leave, take special leave.
They took absolutely everything and were not in the least bit flexible. If someone got a reasonable adjustment, they wanted it too. Even when the protected characteristic did not apply to them.
There was a threshold for sick days, they took the maximum every year. When it changed to number of absences, their sick leave pattern changed too. That was just one example. They knew the HR policies by heart and took every scrap they could wing.
They didn't want to work in between Christmas and New Year and school holidays because they had DC. Every year they tried to book the best holidays off at the start of the year.
Everyone had children If other people had already booked off half term, they would kick off. If they needed them, they wanted names in a hat. If they booked them, it was first come first served.
If they were scheduled to be in over Christmas, they always call in sick. We had a skeleton staff requirement. It meant we had to up the number of people required to cover to compensate. They had 30 days a year leave, flexi leave, 14 days sick leave, 5 days special leave. I have no idea how they got away with it every year.
They did not care about anyone but themselves. They were very unpleasant to be around, lazy and kicked off regularly.