Another thought is that if only careful shots are taken, the pellet won't go past the tree trunk. In the photos of iguanas in trees that I've seen online, they're often stuck to the side of the tree trunk. If there's a tree trunk on the far side of an iguana, that pellet ain't going very far.
I didn't watch the video that the OP linked, but in reference to the image shown on the link of her holding a gun in a parking lot.....I can't imagine she'd get very far without the cops smashing her face into the asphalt unless she had permission or was even hired to be there.
So I agree when you say that shooting up into a tree is not automatically a safety issue, for two reasons: open water/empty field downrange, or tree trunk behind the iguana so pellet stops right there.
I'm guessing the big red moderator is sort of her version of orange muzzles on replica airsoft guns? A sign that I'm not out here with an assault rifle, but rather out here removing pests. Now, throw a pest control company logo on the side of the vehicle that she traveling in, and likely near while shooting, and now you've got yourself a legitimate pest mitigation strategy. I've read the iguana dropping make an awful mess. Many in her neck of the woods might be quite glad at the prospect of not having slimy iguana poop all over their sidewalks, poolchairs, picnic tables, cars, etc.
Seems like I remember reading somewhere that she's a wildlife biologist.
After all that, I am surprised that this flies. However, we are talking about Florida here so.......
