A lot of designers have the bag limit/30 day period. Saks and Neimans have been doing this for years. It usually happens when stock is limited and resellers are buying them up and selling them above retail on eBay. 2 bags/30 day period is actually generous, as most designers limit you to one! (and it's per style, not designer) I was browsing eBay yesterday and was sickened by the inventory and prices of some eBay sellers. I know a lot of those sellers bought their bags before the price increase, yet they're asking above the CURRENT retail price. I realize there are eBay/pp fees, but when you do an auction, the eBay fees are $100 max, so the fees aren't as high as the profit some of these sellers stand to make.
Maybe with the limits in place, more luggage bags will become available for the buyers who really want them for themselves, rather than the resellers who want them only to profit.