And ultimately, if it causes lenders to leave, it's a bad idea. The whole point of all this is to provide a way for margin traders to borrow USD. If there's no lenders then there won't be liquidity when the borrowers need it. BFX needs to do something soon. The easiest would be to outright disable FRR, however that's a temporary solution at best.
BFX are of the expressed and understandable opinion that they're not in the business of guaranteeing a return to swap providers.
If people leave then the remaining pool of funds will become more expensive to use... if that happens to coincide with a sudden reason for increased demand then maybe it'll get a little crazy before those who left get themselves organised to return. As someone putting money into swaps I somewhat welcome the idea; even just one mad week of stupidly high rates would renew my flagging spirits.
Whatever happens, it'll sort itself out in the end - if the demand is there without the supply to fill it then rates will rise until they're sufficiently enticing, even if there's some "stickiness" in both directions (people hanging on past the point where they start to feel unhappy with the return, or taking time to arrive as and when rates come back up).