I could be wrong, but I think it depends on how you achieved your last Gold, if they knock you down straight to Blue, bypassing Silver.
I think that if you earned Gold by the full 16 stays for example, they would knock you down to Silver for one year, if you didn't requalify.
If you earned your Gold by promo, match, challenge, stay just 2 more between such and such a date or any other method other than normal...then I think you get sent right to Blue.
I could be wrong about that, but there are enough folks around the office here that seem to support that theory to some degree.