Hyper-aggressive lawyering by a powerful entity can be an early indicator of how they treat people and use power.

The important thing is to actually read and understand the agreements that employers expect you to sign.

Some examples of what would catch my attention:

* Restricting what activities you can't do on your own time, even when there's no harm to the company.

* Playing games with definitions (especially key terms like "Invention") and loose language (like "related").

* Requiring unnecessarily high burden of proof, for example advance description of all IP that you have created and want to exclude from assigning to the employer.

If you see something you don't like, negotiate changes. If the employer won't work with you to make an acceptable agreement, then don't sign.

Edited for clarity