It is not as good now. I'm pretty sure the warning happens 2 business days after now (around 11 AM EST). 75% and 90% warnings. I asked IBKR to give us something live and they said they would but that was a couple years ago....
Note that the situation might have become less dire compared to a few years ago. For instance, I see that some exchanges offer a similar rebate for PROs. Example:
