For I think the third promotion of this type in a row I haven't received an invitation, at any level of stay. I suspect it might have something to do with my total nights at IHG hotels which have numbered 75-90 per year in the last two years. Of course, this has not stopped me enrolling!
However, I'd be interested to know if others with relatively high levels of nights have been invited consistently on the stay X, earn 10,000 points promos. Then again, maybe it's the color of my eyes