>My most recent 'big' fortune 500 company put me under very strict legal terms regarding what type of software I was allowed to use. Any code I didn't write 100% myself had to be approved by legal before it could be used in software I wrote for them.

Back in the day, this was the norm.

>In reality, the bulk of developers used whatever they wanted with no consideration.

This wasn't - it was grounds for termination.

I remember stuff like - (for Windows C++) you can use Microsoft MFC and Microsoft STL - anything else you write from scratch.

Legal wasn't very flexible back then.

If the other developers did so without asking formal permission, then if the company was sued, they'll just pass it on to the developer.

The happy medium that I've found is to provide a list of acceptable licenses and let lead engineers audit that software to be included obey them.

but still many licenses have legal requirements. i.e. I was working at a fortune 50 rare open source project, we had an acceptable license list but still all the source code needed to be audited for dependencies licenses and the legal team produced the license file to be included in distribution with all the notices as required by mit and apache

I tried very hard to negotiate that happy medium, but was shot down.