For me, the issue is water intrusion into fittings and having it freeze, expand, and cause fatigue and possibly damage to nearby areas.

That said, I know of lots of people who store mast up with no problem. Since we have to transport the boat anyway to store in our own driveway, we take the mast down. To each his own.

But the advice from Westcoaster (and others) says it all: Ignore your friend, find a boat you like, and have a reputable surveyor look at it.