In my exploration of the legality of using a high school track after school hours, it appears there isn't a one-size-fits-all answer. The rules really vary depending on the school district's policies and local laws. Some high schools do permit community access during non-school hours, while others don't due to liability concerns or maintenance issues. It's always best to check with the specific school or district before you decide to do your laps. Remember, just because it's not fenced or locked up, doesn't necessarily mean it's open for public use.