Usually for those that can't ride at a pace to get them back in time for the festivities that go on, most rides that aren't a race are okay with those that need to start earlier. Many are more strict about when the event is over and you must be off the course. Maybe their sanctioning source or other insurance requires that.
The way they word this makes me think they are somewhat okay with someone starting early.
The event officially starts at 5:00 am. Riders will be in a staggered start from that point forward. Any riders on the road before that time are riding at their own risk, and aid stations may not be open when you arrive.
https://deathride.com/f/rules-of-the-ride-road
People do what they want to do. So sure there are going to be some that do their own thing. If it's not bothering anyone then why worry? Or is it bothering you?