Cell phones can be tapped without physical access through various methods, including intercepting calls at central switching stations and using devices like "trigger fish" that capture calls in proximity. Traditional methods involve picking up another phone on the same line, inserting a bug into the phone, or tapping into the phone system directly. New technology has made it easier to tap cell phones, as many calls are now relayed through central systems. Surveillance devices, including hidden microphones and bugs, account for a significant portion of wiretaps. Overall, advancements in technology have streamlined the process of phone tapping, raising concerns about privacy and security.