Yeah, any half decent city IT department will at least be using port filtering for their switches anyways. Unless a port is specifically set up to provide open access to the internet, all OP would be able to do is bonk against the city IT’s MAC address filter until the port was disabled for having an unrecognized device/suspicious activity.
In my building, (and pretty much any city building I’ve ever worked in,) only specific ports were set up to provide open internet access. And usually those ports are in places that need to be unlocked, and which OP wouldn’t have ready access to without a fun little bit of breaking and entering. Because those ports aren’t intended for the general public to use; They’re meant for presenters, speakers, clients who have rented a room for the day, etc… The general public is meant to use the free wifi. Because there’s a different level of service expected if you’re renting a room, vs simply camping out all day in the quiet study area.
When OP tries to bypass that by plugging straight in, the switch will just go “lol git fukd loser” and disable the port. Of fucking course they weren’t able to access anything, because the port isn’t there for OP; It’s for the IT department to be able to use whenever they need to set up a new computer, or book checkout station, or simply to plug their city-owned laptop in to be able to use the city network.