Yeah. Last time I was so "impressed" was when I read about that guy who managed to sell fake bomb detectors to bunch of militaries[0]. It's absolutely brilliant... if your moral compass fell out of your pocket and got driven over by an Uber car.
Morality of militaries is a complex topic. In the real world as it is today, militaries are necessary to maintain peace, so one could argue that providing weapons to soldiers may not always be morally wrong - especially that most of the time, those weapons are never fired against a human target.
On the other hand, selling fake bomb equipment directly endangers lives of the operators of such devices, as well as lives of people they're tasked to protect.
If that's not pure evil, then at least it's a highly refined form of evil.
What about selling defective weapons? Guns that don't fire? Bombs that don't explode? Is it only evil because 'your guys' will be on the losing end of that transaction? Would selling them to the enemy, instead, be moral? What if you believe the war itself is immoral?
Selling non-working bomb detectors can't possibly be worse then being the guy who works on weaponizing mustard gas, or Willy Pete. [1]
[0] - https://en.wikipedia.org/wiki/ADE_651