How about allowing for spies to be prosecuted and tossed into a 2 min penalty box?
In the recent past while playing in several campaigns I and others noticed what could only be spying. For spies to operate with total immunity is wrong. I suggest that there be a small amount of friendly fire allowed in PVP. It needs to be enough that if some number of friendlies (15-20) hit you then you end up dead and with a 2 minute respawn time; a penalty box. I would allow only one hit per player in a 10 minute interval. That would allow us to prosecute spies while requiring some level of jury decision. The spying in the last week was pretty blatant and demoralizing in terms of game play. There is nothing to stop an out-of-group "friendly" from popping siege shields on stealthed players or following a group to report on strength and direction of the force. This would make spying a part of the game but not one sided or out of control.