@ Anon Coward...Re: re: So ZeniMax is now claiming ownership of Carmacks mind?
First, if you work in a large enough company, they will have a set of boiler-plate paragraphs in the contract which states the following:
1) If any paragraph is found to be invalid, then that paragraph is invalid, the rest of the contract is still in force.
2) Anything you design, create, work on, in terms of IP and the work products are the company's. Regardless of if you did this on your own time, or on the company time and equipment.
3) There is usually a third paragraph which allows you to identify all IP that you own prior to the start of working at said company so that you can walk away and continue working on said technology.
If said company doesn't have that agreement in place then someday in the future...
If you work in IT and you are high enough in the food chain where you know what's in the sekret sauce, you end up getting called in to the office and handed a piece of paper to sign. They also have two other envelopes. One contains a check (bonus) if you sign the papers. The other contains a separation agreement.
The 'bonus' would be the consideration owed you for signing the contract in order to make the contract valid.
The separation agreement, wouldn't be shown to you, or even mentioned or implied. Then it would be coercion and invalidate the contract. The company may or may not terminate you for not signing the document, however most will because it means that they can't trust you nor can they protect their IP. This all depends on how paranoid the management team is, or how valuable the IP is.
To your point, you're confusing state laws governing contracts and the companies based in said state, against the laws governing IP ownership.
Non-competes can be enforceable if written properly. IBM does a pretty good job if you're asked to sign an employee agreement beyond the basic one. ;-)