i got no problems with pres wanting to play other pres but then they should make it clear in the title. if the game says something like "have fun" then i expect an enjoyable game for both sides. if the title says "no noobs", "be good" or "average" and a noob or some guy with 20% wins joins, then the host has to check and tell everyone (asking if its ok) or he should talk him out of the game and eventually kick. and if under these circumstances the host is in a pre then he should put that in the title. if its not in the title i expect everyone to play a fair game. and fair game means even teams.
i dont play fair games all the time and i know that, but i try to do it more often every day as i experienced myself that it sucks otherwise.
i dont have a connection to host more than 3vs3. if i want to play 4vs4 i depend on others and there are really nice people out there who care about balance. but these guys who care are not premade!
so there are these premades hosting games like "mid" or "be good" (nothing like "pre", or "looking for pre") or something similar and having 80% stats themselves. they dont even try to balance the teams and even worse kick you if you tell them that the teams are unfair and the host should do his job.
so where is the problem to kick a beginner out of a "be good" lobby? btw. i very rarely host games but if i do the title doesnt say something blurry like "be good" but tells hard facts i.e. min 100 games, 40% wins+. ive not come across many beginners who say "im not good". most come from singleplayer mode (if they played it) and think they are awesome out of the box!