I'm also in the snowbelt and wouldn't be concerned. 3/4" of ice weighs 4 pounds per square foot. A 25 foot rectangular barge with 8 foot beam would pick up 800 pounds. A pointy sailboat considerably less, say the weight of three adults. Would three adults spread around the boat deflect the cradle or jackstands enough to damage the boat? Doesn't seem likely to me.
A 10 foot boom with covered sail a foot wide would pick up an extra 40 pounds over the whole length. The topping lift would see half of that.
If water has gotten into cracks and froze, the damage is already done.
On the other hand, getting the ice off would involve a lot of pounding. Cold plastic won't like that very much.