>Giving 50 cent for a restaurant when only using the bathroom is just a sign of good behavior in my view.

Why? If you're already eating there, why should you pay to use the toilet? And if you're not eating there, then why are you there to use the toilet? Just use a public one. If there aren't sufficient public toilets, that sounds like a failure of the municipal government. Any good city should have lots of public toilets outside, in train stations, or in large shared buildings.