@phaedryx No, I’m thinking of IP address.
Even if the police track it down to your router, that’s not enough evidence to incriminate you. If they find no child porn or whatever they’re looking for on your computers AND your wi-fi is not password protected, there’s not enough probable cause to even place an arrest, let alone prosecute.
According to a Google search, the main reason people use wi-fi passwords is not to avoid legal issues, but to save their bandwidth and ensure high Internet speed that can be slowed down when multiple devices are running off of one router. That sounds more realistic.