Which they can do by finding a way to load a lot of JS that doesn't trigger the popup (someone below mentions running eval on a png). This will likely make the site even slower to users but there won't be a popup.
I've found it best to never assume that intelligent creative people will choose the specific approach I want to solve a problem.
I've seen it happen in sales, you focus on add on warranties at head office, store level they convince customer to buy cheaper product and sell the warranty (now if the margin on the warranty is high enough to offset that might be a smart move) or in one memorable instance give everyone a discount equal to the cost of the warranty..
We did wonder how that branch was selling more warranties than the next three best performing.
Judging it by KB of data just doesn't make sense, unless you apply it to everything. And then it would show on pretty much every site.