This is the way I look at it.
You leave the pin in:
1) True you wont have a chance losing your mast if you turtle, but really, your shrouds shouldn't be loose enough for that to happen anyways.
2) If one of your shrouds breaks, you're running the risk of damaging your boat to the point where it could be unseaworthy while you wait for a tow back. (ie, the mast hits one of the hulls and puts a big hole in it, I've seen it happen)
You take the pin out:
1) if you lose a shroud, the mast will pop off the ball and go right into the water. It will still be connected one way or another to the boat so you can retrieve it, but it will be difficult.
I've been through two masts leaving the pin in. Take it out. Save your spars and your hulls.