Where on Earth does that come from?

I personally think all the people going on about how the person paying for the room should get the least comfortable bed out of "politeness" are being beyond ridiculous. It works both ways, if it's impolite to not take the sofa then it's impolite for the other person to accept the bed.

Unless there's a reason why I shouldn't (e.g. they have back/medical problems or any other extenuating circumstances), if I pay for the bed then I get the bed. (And I have no money and few points/miles...)

I take it if any of you have a guest over at your house you move out of your bedroom and give the guest your bed while you sleep in the spare room/on the sofa?