Does the BitShares price feed reference last traded prices at weighted exchanges or does it average last traded prices over a certain amount of time?
What I mean is there is that there is usually a 1-2% spread between buy and sell prices for BTS on BTC38 and Polo.
If you are force settling and you know it will reference last traded prices at a specific time then it would be in your interest to make tiny sell trades so that the last traded price is in your favour by 1-2%. It your force settle is going through at a thinly traded time it may also be in your interest & very cheap to move the price by another 1-2%.
That would assume that you know when witnesses publish a price and how many witnesses publish it ..
This could be fixed by tracking trades over time or running a weighted average over time but that involves alot of work to upgrade the feed script into a time-sensitive feed script.
Fortunately, this time-sensivity is also achieved by different witnesses running their scripts at different time instants.
We may consider replacing the last price with the "(highest bid + lowest ask)/ 2" that would make it a little more "fair"