I don't think there's any cause to panic on Hilton yet. I've gotten credit for all of my Hilton stays except for my most recent stay, which just occurred 6/29-7/1. An email I received from that property after that stay shows my earnings in HHonors as well as my BMI earnings--4000 points for the two nights (the very end of the double miles promo).

I suspect that this association will end soon, whenever Hilton's contract with BMI ends--it surely won't be renewed. But, I think there will be notice, whether from BMI or Hilton. If nothing else, the Hilton site will simply reject further attempts to use BMI as an earnings partner.