@BalooUriza
The non-compete clause was in every contract for every job I had in Silicon Valley. They were seldom enforced.

What was more common was company A would threaten company B if company B hired a lot of company A's employees.

I definitely ran into the problem where I couldn't get a job at certain companies if I was currently employed at one of their competitors. Apple and Google famously got in trouble for this, but it was more widespread than just those two.