My company teaches the words "Hazard on the right/left", the Cabin crew must evaluate the situation themselves, and even if they manage to safely dispatch one or two passengers from an exit deemed "dangerous" by the cockpit, it is one or two extra lives saved.
There have been many incidents where an exit was initally used, saved a few lives and thereafter became unusable and unsafe, those saved souls are thankfull for the limited oppurtunity they got, due to a cabin crew's evaluation of external conditions, and those that had to re-route because of a dynamic changing situation where also thankfull for not being bundled out of an exit into harms way.