so I'll ask....why would you want to?
I have mine disabled/bypassed using the NAV-TV unit. It also removes the lock on entering an address in the GPS (which I use a ton) while moving, as well as being able to add front and back cameras. Regarding unlocking the DVD, we've taken some long rides where one of my kids has been in the passenger seat and watched movies or tv series while I drove. Kinda sucks unless it's a movie you like to quote
I've also done it driving by myself. Put in a concert or a comedian's standup DVD and listen to it while driving. But I know what you're getting at and I've seen some people pay more attention to them than they do the road. On a drive to Chicago one year I had a guy pass me about 5 or 6 times over maybe 3 miles. Kept speeding up, then slowing down. I finally had to look and I see him reclined wayyyy back and there's a movie or something on the head unit in the dash. That was enough for me to risk a speeding ticket and put a lot of distance between us.
I don't know if the Dodge head unit will let you turn the screen off while a DVD is playing or not (would be nice), but the Kenwoods I have in both of my other cars do, so it does eliminate the distraction so you can just listen without feeling a need to look down at the screen.