Do you have any legal knowledge to back up this position, or is it just baseless fearmongering? The laws we have are already restrictive enough, without making stuff up. So, what is the legal basis for your position?
You have the burden of evidence flipped. Contracts are valid unless found otherwise by law. There have been a variety of exceptions carved out from what's allowed in employee agreements over the years. The right to generate a portfolio of one's work history is not, yet, in that list of exceptions.
As a programmer I don't make videos, I write source code. We're not talking about me waltzing off with the git repository, but of me videoing my software as it does what it does. I for one, after 20 years experience mind you, have never signed a contract explicitly forbidding me to make a video of the product that I worked on running. I think that most other programmers are in the same boat. Which means that for most programmers, unless you are aware of a specific legal protection afforded to viewing software in action, your advice is scaremongering, and not helpful.