We looked after a cafe who had a couple of PC's to use that gave internet access. Yes this was a while ago, way before smartphones and wifi. The PC's had some software that allowed internet access for a set duration based on how long they had purchased. This software was managed by an NT4 Server backend.
The owner called one day to say nothing works. When I got there, NT4 has been wiped and replaced with Windows 98. Apparently one of the university student baristas was asked to help when they had an issue. The owner was trying to save money from calling us out. Fixing this mess was way pricier than whatever was wrong previously!