Boss admitted to (illegally, I assume) claiming all employees digital tips as his own through Square. Should I use this as incentive for him to give me extra Saturdays off (while informing other employees) or should I quit outright?

If this is illegal, I do not have proof other than a conversation that I overheard. He knows I am the only one who overheard this conversation so any legal action would result in consequences and definitely me losing my job and other (surprisingly good) connections I have through this job. Advice?