gman...this is the beauty of advertising! Doesn't have to be 100% correct. For instance, waterproof comes in scales. If it doesn't say 100% waterproof, then don't expect it to be. They would win that in court, because I bet that it does prevent some water coming in. Similar issues are seen with 'waterproof' jackets, gloves, etc. I bet the float plate does help float some (say you lost one ski fighting a tree...). Choice of wording I guess.
Please note, I have no stake in this, but am always amused at advertising. See, I have to listen to drug reps all the time tell my profession about how great their junk happens to be. And they never lie, they just don't tell the whole truth. People have degrees in this: marketing. So, as with anything, I guess we just keep reading between the lines.
Cheers!
-T