Unfortunately the FCC doesn't seem to do much when it comes to GMRS violations unless there is some form of interference with emergency services. This leaves repeater owners to fend for themselves. I have just gone through this myself about a month or two ago. Unfortunately, my only solution was to change to a split tone system leaving the original tone on output, and changing the input tone. (Example, if the repeater is using 141.3 for in and out, change the input tone to 146.2 and leave the output tone at 141.3) This can be a hassle for some bubble pack users who cant do split tone, however it seems to clear up the interference rather quickly. I have not had any issues since (Knock on wood.) The other thing is that you shouldn't post the new codes publicly, and instead require people to request access into the repeater. This helps you to keep track of who is on the system.