Just shared by our reader @口亨口亨，IHG has sent out email invitations about a “Make Every Night Count Twice” promotion:
You can try your luck here. If eligible, you’ll earn double night credits for paid stays prior to April 22, up to a maximum of 10 extra credits.
I haven’t received the email (yet) but was able to register successfully. The additional night credits are convenient for reaching IHG status and earn milestone rewards.
Didn’t work for me in the UK (current diamond) and got double nights last years
I’m also Diamond. We shall see if there are other variations.