I let my Bp go wherever he wants, face, neck, arms, shoulders... He really likes going up and moving in and out of my goatee. Sometimes I have to move him out of the way because he will wrap himsself around my neck then head over my face so he can rest his chin on the top of my head and his body is covering my oeyes so I have to push him aside so I can see what I am doing. At night he will spend most of his time wrapped around the inside of my heaphones while we watch a movie together, constantly reaching his head over to lick my nose or eye. I do not worry about it at all, he has never hissed, coiled or struck at me. I pat him on the top of the head and rub the bottom of his chin and have never so much as had him flinch.
Like a lot of other have said in here, it all depends on the individual snake and how well you now hin and how comfortable they are with you.
And as for the Salmonella, that's a joke.