[gruez]

That's reasonable until you realize that most people are very busy and don't have enough time to read every contract they sign. Not to mention the amount of peer pressure they might be under from the staff ("just sign it, it's just standard stuff"). Plus almost all of those contracts are on a "take it or leave it" basis, so if they do not agree, they just wasted their day and have to reschedule with another shop, who might also have the same clause in their contracts.