Personally I find the DIY version of this far more clever and interesting than the plastic Amazon junk. Too bad you didn't show a picture of it, unless you didn't have rights to post it.
If you absolutely MUST order something from Amazon, get a corkscrew for $5.58, save some money, then make your own sprayer as shown on the original story. Or go to a junk/jumble store and pick one up for a buck so you won't be tracked by the man doing stuff online.
Additionally, the Ai Weiwei version allows you to stand directly under the camera and out of its field of view. The Amazon one isn't like that, and forces you to stand farther out (and in the FOV) if you want the spray to go directly onto the camera.
So all in all, I'd say Ai Weiwei's is a superior solution as it is DIY, cheaper, gives you greater security, and has the added bonus of letting you toast sticking it to the man (or the man's camera) with a glass of wine from a bottle you opened with the same tool you used to spray.