The other day I was having connection issues and I had a nice group of setoners repeatedly let me test different potential fixes. We’d go into a game, play a few minutes, then leave. No rating change or anything. Same teams each time since no rating change. Iirc in 4 tries I was air once, rock once, beach twice. Seems fine. Certainly not something like the highest get a certain spot, otherwise Nory and I would have been in the same slots every time.
I’m about as confident as I can be without looking at the code that it’s random, just sometimes bad rng. I’ve had losing streaks where I got front or beach with a weak team 10 games in a row. Happens when you have thousands of games played I suppose.
Edit: the one actual game I’ve played in months was an opti balance, non-mirrored iirc, where I was the highest rated on my team and was on air and I was vs Yew as the highest rated enemy on air, just as rng.