I'm going to disagree with both of you.
ERICOPOLY: If you throw a die in a completely dark room you don't know what side is up, but just one answer is right and someone with perfect knowledge about everything would be able to give you the right number. Investing in a company that is unpredictable can be similar: you don't know what the IV is, you see a possible range of outcomes, but just one of them is going to materialize.
But if you want to bet on what side is up on the die you can only treat it as a random number between one and six, and similarly for the company you should consider a full range of possible outcomes of IV. Now someone might feel one pip on one side of the die and shout it around in the dark room, and you can reduce the probability that number one (and six) are up and increase the probability for the other numbers. Did the IV of the die change? It still have the same side up, but the knowledge about the probabilities has changed. And for a company you might also discover that some possible outcomes should be removed from the probability distribution. The value of the bet has changed even though the (unknowable) true underlying value has stayed the same. It's not perception that is changing here, it's knowledge about the IV estimate.
Palantir: sure Rimm’s IV is likely dropping. But is it dropping faster than what the market price implies? Is it dropping slower than what the market price implies? I don’t know, and neither does someone who is using a stop loss order. But if you are long something you presumably think that the market is currently wrong about the value of the business, but then when it’s drops the market is suddenly right (or wrong in the other direction)? Doesn’t make sense.