So your ASP .Net friend is saying that all legal documents are perfect and have never been contested in a court of law? Please...

To the end user (customer), for the most part both legal documents and software code are not understandable which is why the attorney or software engineer was hired in the first place. But the end result will be clear when the legal document is exercised (somehow used) and the software is used. If the customer did not get the end result he expected (notice I said expected, not asked for), there will be a less than fully satisfied customer.

Software development goes back to the customer knowing and understanding what they want and then being able to communicate that to the developer, business analyst, or whoever.

I have worked on more than one project where the business users didn't understand their processes, or there were differences in the way management thought the processes worked versus how the end users thought the processes worked, and I have seen business management changes in the middle of a project where the new manager thought the process should work differently than the old manager did. So depending on who you talked to on the business side, you may get a different explanation of what they want (but this never happens, does it).

Do you think any of this might have an impact at the end of the project on whether the software is working as desired?

I would venture a guess that in the legal profession there is not quite as much variability because the outcome of a legal document has to follow set laws for most part. Our software has to meet what the customer tells us it does, and that can be anything.