We split the fee too. If one pulls out, then if we give a day's notice, there's nothing to pay. Like Monday just passed, the drummer texted to say that he is unwell. I texted the other guys to see if they wanted to still go, but then texted the rooms to cancel.
Sometimes just the 3 of us will go & use it to write stuff & make a noise. If it's non refundable & we don't go, then we all pay.