The T&C regs clearly state when an IC BOGO certificate can be used:
Complimentary Weekend Night Certificate:
Upon purchase and renewal of InterContinental Ambassador status a Complimentary Weekend Night Certificate shall be awarded. Each Complimentary Weekend Night Certificate is valid for 12 months from the date of issue and is redeemable in conjunction with a minimum two-night weekend stay at any InterContinental Hotels & Resorts property hotel (not valid at any other IHG brands or for suite bookings). The Complimentary Weekend Night Certificate is valid for a complimentary room night on second night of paid weekend stays. Weekend is determined as follows: Friday, Saturday and Sunday, except in the Middle East where hotels may define the weekend as Thursday, Friday and Saturday. Certificates are valid only for the member who has InterContinental Ambassador status, and are not transferable. Certificate is valid for room and tax only.
Certificate cannot be used in conjunction with any other promotion. Rates openly available are not promotions. Where a member has made the reservation and purchased via Net Wholesaler/Inclusive Groups or through a web site other than an IHG web site, such as Priceline.com or Hotwire.com, or similar booking engines where the room rate is not viewable or publicly available at the time of booking, the hotel can decline the Complimentary Weekend Night Certificate. Reward Nights do not apply in conjunction with Complimentary Weekend Night Certificates.
The Friends and Family Rate is not a "publicly available" rate, and I do not see any way that it can be interpreted otherwise.
Therefore, IHG is not required to honour a BOGO when using this rate.
mxm135
