The reality despite what you or i might do, is that 99% of people don’t carry around an ethernet or hardwire in when there is available wifi.

The library might be public, but it’s still a good idea to communicate your intent or obtain permission prior to using their network in away they might deem to be unexpected.

“Do you have ethernet?” is actually a common library question and the response from whoever works the front desk will likely tell you everything you need to know.

When I entered I spoke to a different librarian about the locked PC room (due to a holiday or something). They said I could use wifi but need to give a phone number to a captive portal, which I already knew. I said is it okay if I plug in over there by the catalog PCs? They said yes. Revealing what I mean by plugging in, well, i was vague for a reason. I know the population has become ethernet-hostile¹ so indeed asking for forgiveness is better than asking for permission in this situation.

¹ Another library in the area has ethernet ports but they are decoys. I asked the librarian what the problem is, why they are disabled, and whether we can turn them on. Librarian was helpless, and said “use wifi”, which didn’t work for me for different reasons than the other library. But the librarian basically said in so many words “not our problem… you can use wifi.” At another library, I was able to connect but Tor was blocked. I tried to get support from the librarian. They had no clue but were also unwilling to lead me to someone who could give support. The way it works around here is security gets outsourced to some unreachable tech giant, and the librarians are rendered helpless. If the SSID does not appear, they can send an email to say it’s down, and that’s about the full extent of their capability.