The hassle and time it takes to leave the park, drive somewhere else and come back would stop me from leaving ONLY to eat off-property. There are plenty of times that I've done this when I was leaving to take a break for some other reason (kid's nap, parks too hot or crowded, some work-related thing). In that case, I'll usually grab a meal off-site somewhere. I also eat off-site sometimes (if not on the dining plan, of course) for breakfast before heading to the parks or a late dinner after I leave.