Some of big tech are so big and dabble in so many things, that it's not unlikely that some part of your project competes or relates to some part of employer's b

Some of big tech are so big and dabble in so many things, that it's not unlikely that some part of your project competes or relates to some part of employer's business, enough to cause IP problems. The process, at least as Google, is to disclose your project to a committee and ask for permission to do it in advance - if they accept they give you IP release waiver and tell you what parts you can and cannot do in your project, for them to not consider it an invasion into Google's interests. My experience with this process was largely negative. Bunch of jerks erring on the employer's side. I can totally see why people with strong interest in their personal projects may not be willing to participate in this circus.