Trying out new heroes in RMM?

http://dotabuff.com/matches/724968394

Does it happen to you that players try out heroes they never played before in RMM?
In this case, invo was randomed and played for the first time (so he had no clue what was going on), and LD was very inexperienced.
I find it extremely frustrating to lose MMR when people play a complex hero, and are not comfortable at all with the hero's playstyle (with LD and invo being among the hardest heroes in the game to master IMO), which leads to 2 heroes out of 5 that have very limited use for the team.
If people don"t care about winning or losing, I would feel so much better if they could spread that mindset only in non-ranked matches. I hate losing when I get very fat and still can't prevent it.

EDIT: I know my bkb came quite late, but that can't explain the defeat.

It happens to me quite a bit, i find people randoming to be extremely frustrating anyway, but it needs to be removed atleast from ranked.

The most frustrating is that people often wait untill the end and then random, completely ****ing up our hero lineup.

Oh yeah, that's probably the worst, especially when we are asking the guy to pick a certain hero that would be perfect, and he ends up randoming a carry.

I like randoming, but would have no issue with it being removed from ranked - it can destablise a match too much either through bonus gold or terrible selections/lack of ability on that hero.

I played one the other day where the opposition team had already randomed a Medusa, picked 3 reasonable other heroes for mid/offlane/jungle and then their last guy randomed a Spectre and kept it. I even got our other support to ward their ancients I was so convinced dusa would farm them. Shockingly, their Medusa/ Spectre safe lane duo failed hard and it was an easy win. Not much fun though.

I had a Terrorblade/ Lifestealer lane against Spectre/ Luna (I was the always-OP Terrorblade). Three hard carries and a carry in the one lane? Can't see that going wrong. Needless to say it was a mess, especially considering three of those characters were randomed - I never random for the 1 in 107 chance of getting Riki. Still ratted out 4 towers, a rax and had 13 kills before they finally killed me :)

Whenever I have someone in my ranked team who randomed hero I just treat him like he doesn't exist and we're playing 4v5.

Correct'd