Good point.

Proper ventilation is absolutely essential when using any sort of flame or stove for emergency warmth, whether it's in a car stuck in a snowbank, an emergency shelter, or any other confined space.I have seen what happens when people fail to do this, and it ain't pretty.

Also, tents are seldom even slightly burn resistant, nor are many modern materials used in outdoor clothing and gear. Stoves sometimes leak, flare up or get knocked over, so I never use a stove in or even near my tent. But, on the other hand, I have used candles and fires to warm different shelters, like lean-to's and debris huts. It's a long-established practice.

It helps to really know what you're doing, and not just think you know what you're doing.