I was doing some pvp last few days just pug runs and started to notice that the teams are being stacked, by stacked i mean the opposing team having friends or fleetmates on the opsit side either to inform on or just impede the other team. If this is what it now takes to win at pvp I truly feel sorry for you. If i am wrong then i am wrong but after 3 days of testing this I believe i am right.
I have seen what the OP describes (one player relaying info back to their fleet), but only like once or twice that I know for sure since closed beta. Usually it's more benign situations.
I can think of legit reasons for a fleet to have folks on both sides though. i've seen it when a player decides to fly with friends from outside the fleet, and ends up facing his own fleet later. And also when there aren't enough fleetmates on their fleet to form a 2nd premade, and they end up PUGing it and get matched up against their own fleet later. However, usuallly when I'm on a team with the "extra" fleetmate, that person generally helps us rather than hurts us by telling us who does what on the other side.
I've seen both of the latter cases happen for us, usually when we're a partial premade and end up picking up PUGs to round us out, and sometimes we end up with a guy from the opposing fleet's team.