Yes, the lost finger thing is common in bad weather. You know how those stateroom doors can really slam shut when they're released from their holdbacks. If the motion of the ocean does the dislodging, and your finger is in the wrong place, it's chop city. It happened to a passenger on our very rough crossing of the Atlantic on Oceania last year. Plus two people died during the high seas. Apparently one of them had nothing to do with the weather. The other was a heart attack. I personally saw a follow spot fall over and miss a woman by inches just a minute before the start of a lecture on the Bermuda Triangle (honest!).
The ship was in a shambles, with major furnishings, like marble tables, cracked in half, and of course, all shop merchandise and liquor bottles on the floor. Depending on what you call "rough," the siege lasted between 24 and 36 hours.
I agree that those who only do Caribbean floats generally have no idea about the power of the seas. But we still love crossings.