I suggest you read about the carder iceman I think his name was. He liked using WiFi from hotels and such as one of his primary sources of anonymity. By the time the police were narrowing in on him, they saw that the IP addresses used by him all came from the same neighborhood. He was at this point hopping between wireless access points, from his house. The police simply went to that neighborhood with spectrum analyzers and they were able to pinpoint him and kick his door in etc. So hoping between different neighbors wireless is not going to save the day if the police are after you. To get the most from WiFi anonymity you need to always be using a different hotspot, but then there are attacks like okay let's pull all the data from the license plate cameras and see if any of these connections we traced back to hotspots correlate with a specific car in the area, or let's pull the list of all people registered at these hotels and intersect them. So even when it used properly, over time WiFi based anonymity can fail you. A single session traced to a single hotel, they are not going to have luck. Multiple sessions to multiple hotels? Okay they might have luck. You would think that being anonymous rather than pseudonymous would help, and in some cases it might, but there is still pattern left to analyze. Okay we traced some suspect to this hotel in this area doing something like downloading CP for ease of example. Okay this happened again in the same area, let's do intersection attack and see if there is anybody to be suspicious of. The technical trace fails but a suspect can still emerge from the crowd.