Wow. Out of curiosity, do you think it should be a crime to walk into a crowded place carrying a bomb? After all, there's already a law against actually blowing people up.
The code is probably a bit more costly than you give it credit for. In fact, it wouldn't surprise me if it were the single biggest barrier to entry an upstart breathalyzer manufacturer would have to face.
But that doesn't mean it holds any trade secret value. Even if there is a reasonable amount of code, I'm guessing it's all pretty straightforward. Most of it probably deals with interfacing between different hardware components, and if your breathalyzer isn't using exactly the same hardware, the source isn't really going to help you.
I suspect the real reason the company wants to keep the source code secret is that if a bug were found, it would be seriously bad publicity.
Causation does not equal causation.
Is that like how having aids is not the same as having AIDS?
Our OS who art in CPU, UNIX be thy name. Thy programs run, thy syscalls done, In kernel as it is in user!