A professional code of ethics with no weight behind it is about as effective as a code of ethics I upload on a random blog tomorrow. That's what ACM's might as well be, since it's not even universally known by professionals, let alone adhered to.
Depends on where you are, in some US states you can get licensed to call yourself a software engineer. This holds you legally liable to the code of ethics. It often influences court cases involving companies too: http://ethics.acm.org/code-of-ethics/using-the-code/
That would satisfy "weight." It's conspicuously lacking in the ACM code of ethics (and basically every other code of ethics someone puts online with no industry buy-in).
