I prefer to maintain a free market. Punishing someone for dumping coins is kinda like flagging Bitcoin that was used for drugs. It undermines the free-market, fungibility, and entire point of the system. Whoever is dumping: it's not their fault that none of us had any liquid coins when Hive was trading x10 at $1. Accounts that sell low don't need to be punished any more than they already are by the market.
We could always guess who's dumping by who sends what to the exchanges in bulk while the price is tanking... but again you'd just be guessing unless you got help from the exchange to violate user privacy.
We could compare lifetime income to current holdings and know, pretty much, who is cashing out.
If stopping the flow of blood from our open wounds is out of bounds, this is gonna be harder than it has to be, imo.