I have some staple teams that I use (and everybody else does too... so not exactly surprising) and some that I swap around in order to better counter what I expect to see from my opponent, and what I suspect are his weaknesses on offense. So talking to previous opponents won't really help at all. Even the "he has trouble with ewoks and NS" advice is not really valid: when I have trouble with NS in one round and I suspect my next opponent might leave NS on defense, I bring a better team. And having trouble with ewoks probably meant he hasn't faced them before and got surprised. Shouldn't happen again. But some players are just bad and will continue to lose against teams because they don't bother figuring out why they're losing and what they have that counters it better.
TLDR: I don't see collusion as an issue, even if it were to occur (and I don't think it does on a significant scale). But puppies are cute!
