The entire point of a contract is to have a document that can be brought to civil court.

If you and your employer don't feel you need one and can rely on ethics alone why sign?

I think the reason why companies want you sign one is because in the event of you leaving, companies can't enforce a word of mouth agreement in court.

Whatever is in your contract is what you agreed to but local laws might superseed your agreement. This doesn't make you amoral if you don't educate a company on local laws. This is solely the company's responsibility.

You get no hero points and your family is not better off. Telling a company their contract is not legal can be seen as a little rude and could give you a bad reputation.