You just answered your own question. There are about 25,000 seats sold through season tickets meaning there are, what, maybe 10,000 season ticket holders (though probably fewer because last I recall, season ticket holders could have up to 10 tickets per account)? So you do the math. The Cubs can easily afford to get rid of 500-1,000 accounts who they deem to be "scalping" when their list is 100,000 deep. Remember, you have your season tickets in their "absolute discretion." They can boot you at any time on their own terms. If their true goal is to maintain season tickets holders who they deem to be "loyal" then I don't think they will have a problem finding 1,000 more people who will not sell more than, say 20 games, on Stubhub. Do you?