Dynamic Queue and how it promotes intentional feeding

As we all know, Dynamic Queue is a very easy way to boost players. The easiest way to do this is by having someone who has a lower mmr than they deserve. The easiest and old-fashioned way of losing mmr is to lose. Now there are lots of ways to lose on purpose. Some are very obvious and some aren't. All people have to do is lose a few games by playing sub-optimally yet not obviously intentionally feeding then afterwards, queue with their 'friends' and then try-hard. I don't think Riot particularly cares about this issue much at all and even if they do, do they have a method to detect it?