I have been an Amateur for 20 years and had a 70 cm repeater up until lightning took it out. I have 3 GMRS repeaters. I only require permission for one reason. I want to verify a valid license for the user. I've never denied anyone permission to use any of them. I do restrict one of them to Emergency use or roadside assistance because it is an older machine, and keeping traffic on it low to make it last longer. I only want to know something about my users, and verify a valid license. With the proliferation of the Chinese dual banders, anyone with $40 can access my machines and make up a call. I've seen this happen on amateur repeaters. Call me cautious.