I specifically recall 444 Sqn from Goose Bay conducting a SAR launch into questionable conditions about 10 years ago that resulted in the total loss of the aircraft and nearly killed the crew.
When I was training to become a Maritime Helicopter Crew Commander, a very wise old Major told me something-
"By all means, do everything that you can to launch. But just remember, you are not contributing much to the search effort if you, too, end up sitting in a life raft at the datum."
In other words, a SAR launch does not suddenly make you magic and suspend National Defence Flying Orders, the laws of aerodynamics or make you immune to weather.
In my own experience, I have refused a medevac launch when holding SAR standby (the Cormorants were broken). In one case, I knew it involved a pregnant woman in distress that needed to get to a better hospital. We didn't go because I could not figure out a way of: a) not dying on the way to her location b) not killing her on the way to the hospital. And believe me, I agonized over that one.
The worst thing that could happen from all of this is that SAR crews find themselves under perceived pressure to launch, no matter what. All that will result in is dead crews, wrecked airplanes and nobody getting rescued.