In many places (banks) there are legal reasons for this.

I've worked at three big banks (in three different countries actually). We've always had access to stackoverflow.

This is nothing that can't be addressed through training. Questions on Stack Overflow with generic code actually get better responses than those bogged down with irrelevant details. You should strip out all labels, namess, even extraneous fields that don't matter. It makes for a more generic problem and solution pair that can help others as well, and eliminates the problem of leaking proprietary information.

Maybe about half the time I end up answering my own question during this step. The act of genericizing the question ends up giving me some new approach, which either works, or leads me to new existing questions-and-answers.

Yeah. When you remove all the confusion, the problem is usually pretty obvious.

Can you elaborate on this?

IP protection. In a prior life I saw someone fired for mailing a model to a home account. Pasting code to a public website would violate similar protocols.

What sort of company do you work at where every employee obeys every directive?

A company that trust their employees. There are so many ways to get around this anyway so it doesn't make sense to try to enforce it in the first place (considering the issues that follows).

What sort of company do you work at that this sort of crude blocking attempt would actually work?