Sometimes, it is just a bad idea. It may seem very sophisticated and smart, but it is not.
Why not keep it simple and keep your customers happy.
Avoid disappointment and stop with those Special Event Cards. As customers we deserve a better treatment. Dont play with our money - leave that part to us. Please.
"Special Edition" cards I support. As long as there is something special about them. A unique outfit, a first release model, a "girl of the month", bonus content, or something we've not seen before.
And, as long as there is a way for ANYONE to be able to purchase it after the "promotion" period is complete. Nobody should be denied access to a card because they are new to iStripper, have a small collection, or have purchased all the cards already. It just doesn't make any business sense.
That's why I proposed the above. Let people "earn" the Special Edition cards via promotion if they wish. Or, just purchase them as normal when the promotion is over for a small premium.