Streamers are an idea, but to be honest, I’ve seen P3 pilots crash into each other and they wouldn’t have had streamers. It’s a good idea to stay away from other pilots at all times, no matter what their ratings are. I just assume none of the pilots see me, and I fly away from people. You want my thermal that bad? Take it, it’s not worth fighting over.
The only people I will fly closer to are those that I agreed to fly with that day. We both know each other, we know we’ll get a little closer, but even then I’ll steer away if they get too close for comfort.