The amount of water you swallow when taking a pill is going to quickly heat up. But, I can see the logic. Ultimately you want the stomach to be as receptive to the tablet as possible and if you scrunch it up by hitting it with something cold, this may slow the absorption process, maybe. The other thing is that with a lot of tablets, we want them to dissolve in the stomach and well, it is known that things normally dissolve quicker in warm water.