The main reason for these clauses is not to steal employee's personal IP, which in reality wouldn't be worth much according to expected value. The main purpose

The main reason for these clauses is not to steal employee's personal IP, which in reality wouldn't be worth much according to expected value. The main purpose is to prevent employees suing their (past) employers for copyright and for companies to assert full ownership of their IP in situations such as acquisitions and IPOs. It removes doubt that any critical IP might belong to employees. A contract is just an initial template to speed up the negotiation. You can often request exemptions as long as you're specific about it. I've seen this clause plenty in the UK and I've also seen it amended.