Can you print on the back of ticket stock?

That is custom printing unless you get a printer that prints on both sides. BOCA makes these but they are very pricey.  Why don’t you print the policy on the bottom of the ticket?  Remember you are definitely limited to the amount of text that can fit on a 2″ x 5½” thermal tickets?  If you emailed the tickets, you could send a receipt that would display your ticket policy.