I've heard this argument ("Locks keep honest people honest") so many times, and I'd like to relay a little story from a couple days ago.
I do firmware development for deeply embedded systems. Typically each platform has a selection of cross-development toolsets. For example, for ARM Cortex M3, you can use a GCC variant (Code Red, RIDE, etc.), IAR, Keil, or a few others. These are niche markets, relatively speaking. Instead of buying a $199 Visual Studio license, we're talking $5K-$10K per development seat, unless you go the whole open-source route (right now, let's just duck that issue).
I recently bought a license for one of the commercial/proprietary offerings, it works very well and more importantly it's mandated by the customer. Fine.
Here's where it gets tricky. The USB security dongle, and the associated PC software, was such a pain in the balls, I spent almost 3 hours messing with the thing, re-installing, calling tech support (who was helpful and sympathetic, FWIW). I finally got everything working, just moments before I started crushing granite in my bare hands.
At the end of my last phone call with tech support I remarked, jokingly but seriously, "You know, it's stuff like this that makes me want to just pirate the software." Tech support laughed, apologized, and all was good.
This experience and this concept wasn't new to me, but please let me re-iterate: (1) Good, honest people will pay a fair price for things that warrant it; (2) Pirates/criminals never will pay, almost regardless of price; (3) DRM and anti-piracy measures that frustrate, insult and infuriate your paying customers really do backfire.