I cannot. But I do know that people who are flying on a drivers license could easily have all kinds of mental conditions that might make them do things a person with a medical would not do. Because those mental conditions would never be certifiable medically. Long and short of it, I don't think that being able to fly without a medical is something that we should allow, as it doesn't comply with ICAO standards and AFAIK, there are no other countries that allow it as well.
Would I be ok with flying on no medical after someone had obtained a 3rd class medical and let it expire, perhaps. But to go up without ever having stepped in an AME office, I cannot support.