Do they plant the evidence on him in the McDonald’s, or is it just in a bag at the station and it’s “found on him” when they search him there? Planting it publicly seems hard. Would have to give every officer a bag of “evidence” or know who was going to respond to the call. Besides the whole not getting seen planting it by the public.
Heat maybe? Hair in general helps trap heat, and in the rainforest that’s not so helpful. Hot and humid I imagine you want that sweat to evaporate as fast as possible. All the airflow.