I think it means "provide government-issued photo ID to get a password which can be traced back to you". The context is if someone using the cafe's internet in

I think it means "provide government-issued photo ID to get a password which can be traced back to you". The context is if someone using the cafe's internet infringes on copyright, the copyright holder needs to find whom to sue. That is not possible in a "type a random email address" mode.