I know that there are a number of theories about what causes the sleep of death. I've gone through two phones and observed a number of different circumstances. I have seen, in other places, a suggestion that is similar to the one here about putting tape on your battery, and that is use a slightly wadded up post-it note (or similar) to reduce the possibility that your battery will shift in its compartment.
Regarding heating, yes, very frequently the phone gets warm, but my experience is that this happens AFTER entering sleep of death mode. To be clear, it doesn't always seem to get warm, but I know that when my phone is in my pocket (or even just sitting on my desk) and it seems warm that it won't wake-up without a battery-pull.
Also, to be clear, the battery-stuffing does not work 100% of the time, but it has reduced the battery-pulling from predictably 3-5 times a day to 1-2 times a week, demonstrable and repeatable, so I think it has something to do with some insufficient margins of error in the battery compartment or in the battery connector area.
Your mileage may vary.
Cheers!