I don't think so. Remember I wouldn't let them off scott free. They would be charged for any loss in the subsequent future sale, they would be liable for the interest, and they would incur a 1% fee. That could still come up to 10%. However it accounts for those situations where a sale falls through, but the person only took up 2 weeks of your time and you got another buyer straight away the next day so you didn't really lose out any more than maybe $1000. Sure take that $1000 and maybe a bit more from the guys $80 000 deposit, but it's not fair to take the full $80 000 off of some poor guy just because finance fell through.
I don't know many people that would just sign random contracts because "Hey if I only waste a couple weeks of their time and they find a new buyer quick it will only cost me $9000 but could potentially cost me $80 000". I think that's still a deterrant for potential buyers considering stuffing vendors around.
And why does it have to be a global judgement? At present it is a situation left to the discretion of the seller regarding what they will do about an individual. Is that individual all of a sudden going to go out and put 10 contracts on 10 houses next weekend because he's been shown mercy with his last contract? I don't think so.
Look the way I'm thinking about this isn't foreign. It's the same way bond works. Bond is paid and given back less any losses to the landlord such as leaving early, or damage to the property, etc... However if you pay $80 000 bond, and you've only done $10 000 worth of damage, what ***** of a landlord would demand the full $80 000!