After being Diamond for two or three years, my HHonors stays fell back sharply last year as they raised their rates (pretty much all my stays are on my own dime and personal budget) and cut back on promos, while other chains (mostly below them) didn't quite as much (on either count).
The other day I got a Gold card (through 4/08) in the mail. The accompanying text said:
We appreciate your continued loyalty to the Hilton Family of Hotels. Although your stay activity did not re-qualify you for Diamond VIP status, you can continue to enjoy many HHonors benefits with the attached HHonors Gold VIP card.
Then it goes on describe the (targeted) bonus offer of 7500 bonus points every 3rd stay between May 1 and July 31 (that some others have also gotten when simply requalifying).
I currently have 5 stays and 9 nights showing in Rolling Tier. The Rolling Tier is useless to me right now, since all it tells me is that I'm Diamond through the end of this month! (It doesn't show any grid at all!) Only one of those stays was in 2007, one in Dec 2006, an award stay in Sep 2006, and one stay each in July, June, Feb 2006 and Oct 2005. All of these except the award stay were 1-night stays. I thus don't see
any way of interpreting the Rolling Tier that would indicate I actually
earned Gold. So I presume they must have "soft landed" me.
However, I bet they look at each situation differently (though what factors they consider I dunno). So YMMV!