Please explain the "guy on the roof"?
Sorry, I haven't been following the paleomedia very well.
Pressure cooker makes perfect sense to me. Nice big lid compared to a propane tank, common, also innocuous. It's a piece of kitchen cookware which does not look as suspicious as a propane tank in many situation such as in your car or being carried around.
I'm surprised at how small the thing is. The only pressure cookers I ever knew were like 10 gallons so you can put 2 layers of canning jars in them. I didn't even know they made pressure cookers that small. I guess people must use them for something besides canning?