I guess my point is that "everybody knows" an AA won't take a loan at 29%, and is waiting to get it bid down. But the one time you're wrong, you won't know until it's too late.
Partially why we (anciently) requested an upper rate boundary on SO's (you know, back in ancient days when we thought SO's were viable).
In the most general terms: I might bid on AA's at a 10% minimum rate, but only on AA's who the "market" judges to be non-ridiculous and bids down to at least 16%. This could have been set up as a "trigger rate" or an "upper bound" or any number of other ways, but... nope.
-t