Agree. Giving every fuckwit who starts spamming GG just because they died at the bounty rune because they didn't notice that the enemy team had 4 stuns at level 1 the ability to concede would be absolutely ruinous. If they want to rob me of a game, they can abandon and get punished for it.
And I'm sure it would be some kind of distracting popup like "fuckface has voted to concede, you have 60 seconds to vote" every fucking 60 seconds.