Most of the items in the goodie bags (last year anyway and I assume this year) are coupons issued by casinos or dealers at the convention. The reason they issued coupons rather than just putting the items in the bag was so people would VISIT IN PERSON. If any casino or convention dealer has items that they want to mail to all the club members, I'm sure that could be arranged, but that it is not the reason they are spending the money for the items. The reason is get people throught the door who will hopefully gamble and spend money or in the case of convention dealers, people that will look over their wares and hopefully buy something.
I imagine the coupons for people who don't show up at the convention will be thrown away . Remember, these are coupons that are worthless after the convention, so why not throw them away?