What a load of woffle!
I've left my 'phone' aka UHF radio on loads of times. Makes no difference at all on the ERJ-145. And thats on the flight deck!
Let the feckers phone if they want to.
Until a neggy safety aspect is founded, I say it's all nanny state pish.
It's not a flying club.
They pay. if they've got 'important' "cough" calls to make. Let 'em!