[CentOS] How can I prevent apache from mounting all home directories?

We use automounted user home directories on our CentOS 6.3 desktops, and on the desktops on which we start apache, I have noticed that all 900+ home directories listed in NIS get (and stay!) mounted.  If I don't start apache, this doesn't happen.

We don't need access to home directories from apache, so I would like to prevent apache from mounting these home directories, but I haven't been able to figure out how to do it.  We use the stock httpd.conf file, and I commented out the "LoadModule userdir_module" line to no avail.  Any other suggestions?

Alfred