Well, not against Australian law, anyway - it does, however, defy gravity. And thereupon hangs a tale.
Actually thereupon hangs a lot of stuff. Manfrotto Autopoles seem to have been around since the 1950's and have been seen in photographer's studios, designer's lofts, upmarket shops, and possibly bomb sites. They are one of the niftiest solutions for supporting things that Manfrotto make. And Manfrotto make a lot of supporting structures!
Basically they are a two-part metal tube with rubber ends that can be slid between two surfaces and then jacked outwards to wedge the tubes rigidly between those surfaces. Note that I didn't restrict myself to saying floor and ceiling - Manfrotto Autopoles can equally well be placed between two walls and locked into place - they can even be used to separate teenagers in a car on a long trip.
They come in different sizes and different diameters so you can come close to the measured span you need to wedge into before activating the mechanism. The wedging is done with a lever and roller and is surprisingly powerful. You must make sure that the two surfaces you are going to exert pressure onto are sturdy enough to take it - no pushing ceiling panels out of place if you can help it*. Once you have positioned the Autopole, wedged it in place and locked off the lever, you are set to hang anything you like off it.
Here's where the Manfrotto 035 Superclamp and other accessory arms come in handy. You can swing 2750 Superior paper rolls between two Autopoles easily with the appropriate Manfrotto Expan drive kits. Don't be shy - I run three Expans and three rolls of Autopoles and no fear of anything falling down. And plenty of pole space left for anything else you want to clamp on.
If you are stuck in an area that has a floor but an inconveniently high ceiling, Manfrotto also make a set of tripod legs that slip over the pole and can stabilise it beautifully - again well enough to swing three 2750 rolls or other heavy gear.
Note that they can also be used for light supports if you use the 035 and side arms - in this instance they can support multiple lights and flags as well.
* I got leery of putting pressure on ceiling panels so I made a pair of big round plywood feet and support tubes for my Autopoles. Looks clumsy, but it means that even if I inadvertently lose contact with the ceiling the whole assembly cannot actually fall over sideways. There's probably a more elegant way but this will do for now.
Steve Sint - my new favourite photographer - has a plan in his book on digital still life photos for a product table made with Autopoles and a couple of sawhorses. Looks a cracker.
Finally, there are time when you need to have a camera way up high. Trust the Autopole and a side arm to do it.