no not hot or boiling water, you can try to give it real minimal stress in the last few day by watering it with frigid water and leaving it in the dark, it will respond by increasing in size and resin content by a small percentage.
I've always heard that you don't wanna water them anymore after 7 days before harvest...if in soil.
Doesnt really seem like watering them right b4 you harvest would make much difference cuz the "warm water" would have the whole mission from the roots to the buds to go through...i wonder how long it takes for the plant to fully quench herself?..think that would extend the drying and curing time and MAYBE increasing the chance of mold and mildew because warm dark climates are perfect for fungi...idk sorry stoned and rambling. :/
this is what i do every time i harvest except you left out the best part. if your drink the water after boiling the roots in it you get super high! seriously you should do it!
what you really want to do is water your plants with bongwater man. then when you boil the roots they suck up all the thc from the bongwater. the resulting buds cure aids.