Can I print more than one copy of my ticket?

Yes, if your ticket is a PDF.

However, someone else could end up sitting in your seat if they arrive there first with a copy of your ticket. Whichever ticket gets used first will alert the system to show that the ticket has already been scanned.

If there's a dispute, your name and the last four digits of your credit card are on your tickets and can help you confirm that the tickets belong to you.