[user5994461]

In practise, it means that holidays days are simply not accounted for.

Otherwise, it's like usual, tell your team in advance and write the days on the calendar.

There is no abuse. If anything, most people don't take enough because it's not accounted for && there is noone to remind them of "you gotta take 10 days before January [or your current quota be lost][and you're gonna burn out because you work too hard]"