After visiting Sydney Australia, I have a better appreciation for the native wildlife that live there including Koalas, Wallabies, Tasmanian Devils, and Wombats. Part of this new found enthusiasm was because we were able to get up close and personal and pet the Koalas at Featherdale Wildlife Park just outside Sydney. Within Sydney, it is illegal to pet the animals and they are lobbying to have all touching of animals banned. Some say this is for the protection of the animals from human diseases or being irritated. Others say the ban is to protect humans from the animals (Koalas are known to get vicious when woken up from their naps).
This was also a controversial subject when Steve Irwin "The Crocodile Hunter" would get up close and personal with the animals in filming his documentaries. His life was ended when he was stabbed in the chest by a stingray. To me, if an animal is tame enough for picture shoots at the zoo, visitors should at least be allowed to pet them. It's obvious when they're cranky because they'll move away from people so you make sure they're on frequent rotations for shifts. I think once you've been able to make a connection with not only sight, but also touch, you'll want to make sure that these animals are preserved for future generations (though in some parts of the world, they're not in danger of extinction).