As these markets continue their chaotic path downward, people's true colors come out. Some people show increasing amounts of fairness and consideration. Others will self-optimize and use every bit of leverage that they can get their hands on.
Two entrepreneur friends of mine recently had a very negative experience with an investor who has a reputation for being Machiavellian and it really, really has incensed me. These slimy bottom suckers use the changing market conditions to test how low they can retrade an existing deal. Here is the standard game plan for these kinds of assholes. When they sense a dramatic change in the market, they pull away their term sheet siting "policy" changes. However, instead of walking away from the deal, they mention in passing that they might reconsider under "different terms". If the entrepreneur bites, they know that they have leverage and they proceed to throw down absolutely egregious terms (multiple liquidation preference, half the original price, etc). If the entrepreneur bites on this, they know they really have them and continue to ratchet down the terms until things break and they back off.
Entrepreneurs who have a retrade occur, must first figure out how badly they need the money. If they can get the runway from expense cuts or manage to breakeven, then they should tell the investor to pound sand as soon as they mention "different terms". Remember, even if you get this round done, you will be stuck with this scum for years to come and any time things go the wrong way, they will use their leverage to take another pound of flesh. This falls into my category of "Life is too short to deal with Assholes". If you have to take the money, negotiate as hard as you can, realizing that they will continue the downward ratchet. Try to drag out discussions and aggressively start talking to any other possible sources, even if under the same terms (if you think they are decent people, at least the match won't burn twice).
Before dealing with someone, especially an investor, find out what their reputation is in ugly situations. Did they roll up their sleeves and help the CEO or did they use the situation for leverage to self-optimize. Animals don't change stripes so assume you will see more of the same with yourself.
If I wasn't concerned about libel issues, I would list a couple of these known predators (with details) such as the one pimping my friends. I can only hope that the Laws of Karma eventually return the favor...