They can write anything they want. It rarely will cost you the job if you object. They just hope you just accept it without question. I encountered this once s

They can write anything they want. It rarely will cost you the job if you object. They just hope you just accept it without question. I encountered this once so far. I told them I would agree but it would cost $50k to reserve my talent for that (6 months in my case) time. Payable up front at signing. The HR guy laughed, crossed it out, initialed it and said "yeah, sorry about that..." And that was the end of it.