If they see it as a scam then they seem to expect certain financial gain from donating. In my opinion this is bad as donating life-saving goods should not be done just for the money.
You can’t be scammed if you are doing it for saving lifes (except if they sell the blood to some shady labs instead hospitals).
I have no serious knowledge about it, but for the thermic aspect I can’t imagine it working in any way.
Your body will try its best to keep its core temperature constant. So you won’t really cool your cells down.
In this process it will burn even more fuel to produce heat, so quite the opposide they want to archive.