Not necessary at all. I have been on 10 or 11 trips with a transmitter on my 1st stage without a hose, and the better half has one now a few trips old (perdix AI). Never had an issue.
I don't have a transmitter for my perdix now, but if I ever got an AI, I would not put a hose there.
I don't have a transmitter for my perdix now, but if I ever got an AI, I would not put a hose there.