I travel with my "dog-pet-friend-companion" and I always have a pick up package in my pocket. I totally understand the feeling of those who would not travel is they couldn't travel with their faithful companion. Yet, why must I wake up in the morning to find that some inconsiderate traveler did not pick up after their pet when it decided my campsite was the right place with the right smells.

I would have no problem having a DNA certificate for my dog if it meant the parks would and could enforce pick up rules for the guests. It might just protect my pet from parvo.
JMHO