Why not have your tech support make a note every time someone has a problem with certain security restrictions and then use the notes to compile a troubleshooting document that all new customers will be pointed to:
Note that our hosting servers use mod_security and suhosin extensions. Please familiarize yourself here and here with the security limitations these extensions enforce.
Then whiny customers like me wouldn't have anything to complain about. I always RTFM
Again, I have no problem with security if I'm aware of it.