Here’s a part of a cabinet in my wardrobe where my printer lives. It’s a bit noisy with all those hard surfaces so I am just about to put up some foam padding on all 5 sides.
Is that stupidly dangerous?
You can see I have a smoke alarm there, but it won’t stop a fire on its own.
Edit: the cabinet has no door, it’s always open like in the photo, but the wardrobe door is generally closed. The room has some ventilation so smells do go away.
You don’t want to pull cold air in but a small fan to circulate the air in the enclosure gives you more even temps from top to bottom and can improve print quality. I installed a nevermore filter a while back to filter the filament fumes and was surprised to see my prints improve too.