The official Vans Warped Tour page just posted the following:

DO PARENT'S GET IN FOR FREE?
No - unfortunately we are no longer offering the FREE Parent Ticket.
Over 21 years the Warped Tour audience has always been for the counter culture teenager. As our audience grew up and changed and as new fans came to the shows, we've worked hard to adjust with them and continue to keep the tour relevant.
In 2015 and 2016, we tested implementing a "Parent Get's In For Free" program that allowed (1) parent to be admitted to the show for Free if they were bringing a child that had a paid ticket.
Unfortunately in 2017 and moving forward, the tour is "going back to our roots" and with the booking of a more balanced lineup including many legacy acts, we are no longer offering the FREE Parent Ticket.
However, any parents who buys a ticket will still be able to come to our Reverse Daycare Tent where they can hang out, watch TV, and keep an eye on their child.

Well. That's it, we guess. Be sure to check out that reverse daycare, though. It's usually the only place non-press can go that has air conditioning.