In most states in the US an (ex)employer is going to have a very difficult time preventing someone from seeking work, regardless of what contracts or agreements

In most states in the US an (ex)employer is going to have a very difficult time preventing someone from seeking work, regardless of what contracts or agreements are in place. Of course, you can chew up a lot of legal dollars in the mean time proving your case. If you really want to pursue this... An employee is not obligated (in most cases, IANAL, etc...) to reveal their reasons for leaving their present employment. Your potential co-founders could simply resign to "pursue other opportunities" and leave it at that. Since it it unlikely you are going to put out a press release upon their employment with you, simply have them leave LinkedIn and other job status tracking accounts unupdated. By the time it is obvious where they have landed your previous employer will likely be well beyond the shock and outrage phase.