What kinds of files within their public_html folder?
If you have specific rules that you don't want them to change within their .htaccess, define them within the apache configuration file(s), or place a .htaccess directly in /home (note, the latter option might cause load increase).
If you want to disable user-land .htaccess files, you can do this in the apache configuration files as well.
I guess a better question is: What are you trying to accomplish? What's the situation that caused this question to come up..?