I imagine this puzzle game would be funny for about 10 seconds, and then your friends are going to start yelling for some TP... or they will put your guest towels to ingenious use, as John Brownlee from BoingBoing Gadgets puts it.
Via BoingBoing Gadgets.
Smack your so-called "host" on the way out. ;)
And it only looks like you need to untie it to change the roll.