I like the idea of the condor-sized bat snatching up small prey on the desert at night, though the web spit doesn't really fit with that - the bat would actually need to land to extricate its prey from the webbing.
I like the feel of this place - it even calls to mind some of the Game of Thrones locales, though the inhabitants are far more hospitable. I see this area being a critical pass between populous regions.
A good place to stage a murder mystery, plague, Alienseque monster invasion, etc.
Good trap, though things like 'no escape' bother me. All illusions, the product of fallible mortals, can be broken with sufficent spellpower or other attributes/resources. Extremely Difficult, yes. Impossible - no. Go to Comment
A culture must hide its hands in the arm of their clothing as a sign of respect and peace. When approaching somebody you show them respect by crossing your arms and hiding the hands in the shirt sleeves. Nobody worries about hidden knives and such, it is the threat of magic that this custom was created to prevent.