The problem with them stopping it when it looks unescapable is that is leaves a lot of room for some very subjective reffing. We have seen fights where fighters are getting pounded on and the refs step in and still there is a lot of discussion on the timeliness of the stoppages. Further, we have seen many fights where an armbar looks deep but the fighter is able to roll out of it.
I was thinking the same thing watching the fight last night, but such a rule would only lead to more and more criticisim over referee stoppages. I would hate to see a title fight inappropriately stopped because a ref "thinks" a figher couldn't escape.
Team Stand Alone #1