I nearly missed that one!!!
Boy, are you asking for trouble!
You may or may not be legally permitted to do this, but EVERY person that has ever bust tables looks upon tips as their money and never yours to dip into.
If you did that to me, I'd take you to the cleaners. Many, many decades ago, I was a part of a scam in a restaurant and we brought them to their knees - and it all started with the management trying to dock tips.
They knew something was going on, because TO was persistently down, despite full tables and a busy kitchen. They even put a theft specialist onto us and he stood right next to the till all night. They checked stock and couldn't understand how it matched TO perfectly. Nothing was missing - except of course a healthy bottom line.
EVERY member of the eight table staff, the cooks and the barkeep was in on it. Getting them to all take part was easy, once the manager was stupid enough to start docking tips, just because some poor waitress had a 'runner' on her patch.
But everything matched. The cash matched the till roll. The sales matched the stock. We ran a tight ship - a damn sight tighter than the idiot manager!
This was a big place and by the time management gave up and rented it out to one of the members of staff (who had the money to take the place over for very obvious reasons!) in today's money, the rent was £14k a month. It was a question of rent it out or go down in flames.
I and the others were all very moralistic people, but as soon as you start to steal from your own staff, the gloves are off. If you declare war on your own staff, you do so at your own risk!