There is: http://en.wikipedia.org/wiki/Sarbanes-Oxley_Act
And unfortunately what you read about the 802.11n patch was wrong. This was a feature released later, and not a software update or patch.
I can't see anything in that that says companies can't give stuff away for free.
As people have pointed out, Apple don't get any more money for the iPhone, yet iPhone updates are free?
I downloaded CrossOver for free (NOT pirated), given freely by the company.
Whether the 802.11n was a 'new feature' or an 'update' to improve from g to n is arguable and a matter of opinion, the point is they charged for it but didn't have to if they didn't want to, same story with the iTouch updates.