In the discussion about libraries in A Feeling of Power, there were some comments regarding the libraries in Maryland, where one of the commenters lives. Quite a while back, I made up a table of all the libraries I could find in the U.S. and Canada that had their behavior policies on-line. You can see that here.
It’s probably been about 5 years since I did that, and so many more libraries have gone on-line and provided their Codes of Conduct, that table is probably rather out of date. I may spend some time trying to update it.
In the meantime, based on my discussion with Tim, I updated the Maryland portion of that table. In Maryland, the library system is county-based (except for the city of Baltimore), so there were relatively few I had to look for. The Maryland portion of the table is here.
One thing that you can see is that about 2/3 of libraries have shoe rules. (Note: this is actually 2/3 of libraries that have their behavior rules online; if a library is not online, or does not have its rules online, it is not included at all in this table.) Maryland is slightly worse: 3/4.