No, margin call is initialized by witnesses via price feed. As I've said, whether a debt position is "well collateralized" is subjective.
> witnesses are able to feed parameters to change fully-collateralized debt positions to undercollateralized when needed.
Definitions are crucially important, so if you don't define terms we will keep going in circles. The bare minimum amount of collateral required is 100% of all short positions. Anything less and you risk a house of cards scenario like mainstream financial institutions are about to experience. We have set a standard of 175% to provide more safety to reduce margin calls, and I've seen comments we could reduce that to 130%, but for some that's not enough.
The last statement appears to be yours abit. Putting it upon witnesses to define what
they believe is too little collateral creates a conflict of power between witnesses and the Committee who sets various blockchain parameters. The minimum collateral ratio should not be determined by witnesses, it should be uniform and globally defined, and that is the role of the committee. It should not be dynamically set by each witness.
Witnesses should be explicitly "reporters of facts they observe" and block producers. Giving them the responsibility to set asset prices (and acceptable collateral levels) that differ from what can be observed in the market is manipulation and potentially opens witnesses up to liabilities and law suits.
When the MCR core bug is resolved we can experiment to achieve a tighter peg by preserving the market price feed and changing MCR or MSSR. Although some may argue that is also price manipulation b/c it achieves an almost identical effect (yet to be demonstrated, but that is general consensus), I don't see it that way.
As I've said and will continue to say, under-collateralization is my main concern regarding BSIP42. It is also Xeroc's and others who have PM'd me. Liquidity and a tight peg are obviously important, but IMHO and others not more than preserving the collateral.
I believe it would also be disastrous to the ecosystem's reputation to renig on the promise of redeemability as some are so willing to do. Yes I recognize redemption to 100% is not always possible but that is not by design as much as it is by the supply and demand of the market.