I agree, it's no where near bulletproof, but it's about raising barriers as well as updating the tool once workarounds are found. I don't see an easy solution to this issue but in most of the cases (including the ones in this article) I've seen to date, a simple URL scan would've caught them let alone more complex methods.
If the only thing looking at it is a machine, then you can keep iterating until the machine doesn't notice anything.