A possible solution is to not ban sales to bots per-se, but instead verify that the identity of the person redeeming the ticket at the door is the same as the person who purchased the ticket (via verifying CC details, or even something as basic as their name).
If tickets have conditions on them that prevent their usage by anyone other than the person who originally bought them, then there can be no market for resold tickets. Let the scalpers buy as many tickets as they want, but eliminate the market for them to be resold.
Ticket Australia now state as part of their conditions of sale "This ticket may not, without the prior written consent of Ticketek or the Seller, be resold at a premium or used for advertising, promotion or other commercial purposes (including competitions and trade promotions) or to enhance the demand for other goods or services. If a ticket is sold or used in breach of this condition, the bearer of the ticket will be refused admission."
If you knowingly purchase a scalped ticket, you're taking a huge risk that you won't get in to the event.