I've heard an 80 year old person did this. We had a party of 10 and several were a bit squeamish about taking the leap - especially the first time. But by the end of the tour, everyone was much less anxious, if not downright comfortable in the harness. Our family photo was all smiles :)
Pros: 1) Safety.Right from the start, the staff demonstrates every piece of equipment and every safety feature. The thrill is in the zip experience and not the danger of it - as it should be. 2) The staff was friendly and extremely patient with even the most timid of customers, 3) A great way to see the animal park. You could tell there were many visitors on the ground that wished they were us!
Con: Really the only suggestion I would have is to stock the gift racks (or gift shops) with sunglass straps and more variety in t-shirts (size and design). We would have bought more :)
All in all, everyone in our party had a GREAT time. I would recommend this attraction to everyone.