I talked to a few people offline and got responses ranging from, "it wouldn't start or run" to "yeah Ive seen that several times."
Here's the scenario: I had a 650 for sale. I never had it in the water but the thing seemed to run fine in my garage. I never checked the compression on it (probably the only ski I've owned that I never bothered to check). A guy comes over to look at it and starts it up. He says, "hhmmmm, sounds weird." (it doesn't sound weird to me, but what do I know). He puts his compression gauge on and the front cylinder reads zero and the back on reads 150. He says something like, "Yeah I see this more than you'd think blah blah blah." Okay, whatever so of course he winds up buying the ski for half of my asking price. I should feel glad that I was able to get rid of the thing but I just have this nagging feeling that he held his finger over the release button on the compression gauge while testing the front cylinder.
At this point it is way to late to do anything about it and I have no proof of anything. I spoke with a guy who owns a machine shop and he said something like, "They don't sound or run that different out of the water, but you'd have a hell of a time getting it to start in the water."
Moral of the story: Make sure that YOU are handling the compression test when buying or selling a ski.