Lol, it's not on me to go figure out how many places require every employee in a fast food restaurant to get some sort of health certification. You're the one who brought that up as an argument for not filling up drinks so you're the one who should figure that out if that's your main argument here.

I do know that in Wisconsin where I live the only requirement for restaurants is that a single member of the staff needs to be ServSafe certified, which consists of taking a super easy exam once every 5 years.

That's not to say that certain restaurants don't require more than that because I'm sure plenty of them do, but that also doesn't mean that a dasher filling up a soda is illegally committing some sort of health code violation.