This is a good point, thanks. I agree that there are stability implications from unwinding basis trades, which we ought to consider, and are inherent to any lending market. These concerns apply to the existing ETH collateral type, though presumably anyone who has wanted to put such trades on has had plenty of time to, so we could assume that this potential is close to exhausted until market conditions change. I think having the DAI supply increase now due to borrowing against WBTC, only to be contracted later if conditions change, probably puts us in not much worse a position than if we hadn’t issued the WBTC DAI in the first place, provided the debt ceiling was under control, don’t you think?
In general I think we should treat the WBTC SF similarly to the one for ETH.