Depends on the company. I've had companies do this for me.
In one large company I won't name, the way we did it was to have someone with enough authority give me a statement in writing acknowledging that anything I made outside of business hours, using my own computing equipment wasn't owned by the company. That was good enough for me.
> anyone below a "department head" is not getting custom addendums added to their contract.
Nonsense. My wife negotiated modifications to her employment contract in her first job out of school. This included a diabolical adjustment to the non-compete clause that essentially made it worthless because it granted her the right to work so long as it was more than one mile away from one of the branch offices.
And since two of the branch offices were more than a mile from each other, that meant she could work anywhere, since any location, including in the same building as one of the branches, was at least a mile from a different branch.
