1. Banknotes are lightweight, so i dont see a reason for it to be an issue
2. Criminal acts? On what form? How they do get involved with that?
It seems you don't know much in the life of travel that taxi drivers and passengers face.
Have you ever seen a taxi driver being robbed and have you ever seen a taxi passenger being robbed?
This is the reason I say payment for cargo taxis is safer with Bitcoin, see what I mean.