I haven't, but I've sure used library internet connectivity, most often when visiting a new city and looking for a place to live. Occasionally when killing time waiting for someone or something while I'm near a library.
And?
Good call.
I can tell you've never gotten to know any librarians. They fight snooping harder than anyone, including the ACLU, at least as a rule.
Sure, there might be something forced upon them, but as a rule you can get access anonymously if you politely explain that you have no identification, and jump through the hoops.