I'd imagine part of the problem is the fact that they're premade and throwing so there's only 1-2 players reporting them. You could get same 1-2 reports if you're playing really well (from enemy team) or really poorly (teammates). Deranking groups in CSGO are pretty big too so I'm suprised they didn't even get a 5-man squad. You could easily get silver 1 without a ban from any rank within weeks. Until Valve puts these players to Overwatch automatically I doubt trust rating will help a lot.

I'm personally annoyed that Trust rating puts me with competely new players at smfc/ge who are either smurfs (potentially griefing, leaving games since ban doesn't matter) or cheaters with <100h. There's really no point for me to not pick prime.