How can you be unsure? I thought I explained it quite clearly. The courts look very poorly upon prior restraint of free speech. Non-disparagement clauses in employment contracts specifically are very dicey and difficult to make stick in a court of law in the US. Here is an article about it... they can end up being enforced, but it is unusual: http://chernoff.law/non-disparagement-clauses-can-really-enf...