I played yesterday the Metro mode and only the zombie map.
The zombie map has ONLY option to play with squads!
8 out of 10 matches I played were with randoms and today I got this message!!!
So what the game is suggesting is:
1. Play only with friends (if you have and if they are available when you want to play)
2. Play SOLO vs squad and get destroyed!!
3. You will play with cheaters and get banned!!!
Very logical, great work!!!!
If you see that a random player playing with another random player, then you can't hold them accountable for each other's actions!!!