I don't know the details, but when I worked for a company based in SF (like Dropbox), they claimed there was a law that compelled them to count sick time and vacation in one bucket.
CA has some really weird rules. In addition to that, there's also a cash-out rule that vacation can't be expired without compensation.
So, managers have to be persnickety about having you track the time you spend out of the office going to the dentist, etc. because otherwise the company can get shafted with a bill for the "untaken" paid time off at the end of the year / when the employee leaves.
Cash-out can be abused, but on the other hand, if you don't exert pressure on your employees to continually work overtime, or take as little sequential leave as possible, that's less of a problem.
Though I know it's somewhat common practice here in New Zealand to start not taking leave if you're about to quit, so you can get one or two extra paychecks when you quit, and time it so you have two weeks to a month before your new job starts.
Same benefit, plus a nice cash bonus.
Not saying it's the best thing to do for employers that treat you right, but if you're not being paid overtime, and being asked to work it and weekends a lot, it's not like you don't deserve getting that back if you leave.
