Something like this might be a deterrent for a company that would otherwise be interested in suing, but it's not going to stop a determined foe from really mess

Something like this might be a deterrent for a company that would otherwise be interested in suing, but it's not going to stop a determined foe from really messing up your life. You'll win ... if you have the cash to fight them (which you don't, unless you're making enough money that a lawsuit is a total non-issue). In practice, you'll settle to stop the legal expenses, and they'll get at least a chunk of your project. When you're successful you have to expect that some people you knew before you found success will get salty and think that you owe it all to them. A few of these people may be inclined to file a lawsuit, including your former employers. They see a pie and want to claim a piece of it.