Is there a case against you when you sign a employment contract that demands 50 bucks per day if you resign prematurely?

My buddy got sued and being summoned in court by her ex-company. Her contract last for a year, in that so-called “bond period” if she resign prematurely, she needs to compensate $50 from the day she leaves up till end of contract. Yet within the contract, the company doesn’t state any sponsorship for any benefits or any bonus given. She got a lawyer and he claims that the contract has no fair amount of “consideration” and sounds like a slavery bond.