I'm sorry, enough said, its very obviously intentional feeding, no human being is that stupid. But it happens so often. Please start removing these people at least from ranked. Or you know, maybe don't match them in my games because they clearly don't belong in them.
And before you ask, no there is never jungle pressure in the lane, they legit just die solo again and again.
No.
You have apparently never seen silver or bronze.
I consider it inting when someone is dying more than once per minute by 10 minutes. Even then it is usually still just gross incompetence mixed with tilt, but the results are the same.
Nope, it isn't always intentional feeding. It can simply be a person having a very bad game, not having map awareness, picking the wrong fight, and so on.
The kind of players you're talking about are the ones that don't have enough knowledge about the game, thus, they can have dumb deaths.
Banning players over this is ridiculous. Just allow them to learn.
I didn't think people were that dumb either until I read your horrible suggestion. I thought about not saying that but it's clear you never thought of the possible consequences of this proposal.
Some people just don't understand how to play They feed and then don't respect how strong the other player is from the gold they got Then they feed more. Happens to me all the time. Once you start climbing, these players will appear less and less They are technically 'banned' from higher ranks. (unless they got boosted)
Gonna be bronze 
purge
