It can be about coordination. Though GMRS has no official coordination it helps others decide a frequency that might be open in your area. I know every repeater operator in the area and we do all things possible not to cause interfirance among though known repeaters. Several are not listed but we do our coordination on our own. This is no way stops someone from putting up one, but allows us to do it and not cause others problems. I recently was going to put up a .700 repeater but someone else did and decided to go to .675 as it was open in the area.