Like many of us, my Harrah's "Diamond" status was acquired thru "Diamond in a Day" - in my case, spending an hour or so on the $5 JOB at Rio, about a year ago. The card was expiring at the end of March and I had no significant play at Rio or Harrah's since then. Fortunately (well, sort of), Caesars and its excellent inventory is now part of the Harrah's chain, so I trundled down on March 31, preparared to spend the evening there.
However, I DO have a ton of history with Caesars, especially last year (but none so far this year), so I thought I'd try Jean's "never hurts to ask" approach and check at the Total Rewards booth. The boothling initially said that I was indeed being downgraded; I responded that I had played at Caesars "a lot" and was wondering if that had any bearing. She typed a bit more, and happily reported that "it's letting me change it" back up to Diamond. I'm now "Diamond" thru March 2007.
The moral of the story: if you have any sort of history at Caesars, Paris, Bally's, or Flamingo, mention it when checking up on your status.
John