Check Mat Team, one of the mos tinnovative and forward thingking teams in BJJ added their 2 cents to the 50/50 debate and took two steps forward as tey released two youtube videos on how to un-lock and to submit the 50/50 :
"Due to the on going controversy about the 50/50 guard, we at Checkmat Rio wanted to add our contrbution. We want to make sure to state that we are not against the 50/50 except when it is used to stall. We already have various escapes and submission to un-lock that guard, here are a couple of options: "
Video 1 (Submission)
Video 2 (Escape)