Dual use, and professionalism

I suppose it depends on the definition of "dual use". If it's been left deliberately vague (so it catches performance testers, as mentioned above) then it's a really poor law. If it's written well and only covers those things that are primarily for malicious purposes, but can be semi-plausibly claimed to be for legit purposes, then it's not too much of a stretch to consider a licensing regime.

It shouldn't restrict "checking the door's locked" to computer professionals though.