Re: Do any of you do this?
I freeze both my stem and my vase if I want really cold smoke, which I do occasionally. To everyone freaking out about the vase cracking, it will only do that if you initiate thermal shock, which is why I fill my vase with water THEN freeze it. There is no sudden shot of lukewarm water to shock the glass and I have never had any problems with either the vase or the stem.
so in short imo freezing is fine as long as you have water in your base before you freeze it, and the stem will be fine.