Often where I work the cabin crew will turn the temp up throughout the whole aircraft in an effort to heat up the galleys where they have to spend the night, sitting by a cold door. During the day they dont seem to do it probably because of the body low during the early hours. We also issue duvets in business and it is impossible to sleep under these when it is so warm. If we notice them doing this we just start to crank down the temp from the cockpit to try and keep it 24 or under, it then usually goes up again so we just keep turning it down until their control would be in the max heating setting but our control is the master and they can only go 4 degrees either way (I think) maybe 2 degrees either way from what we have set. Yeah would be easier to just say leave it at 24 to them you may think but unfortunately not the case most of the time where I work. Also gives us something to do :-)