Scam emails to sellers

I am using a classified ad system, and my users keep getting spam and scam emails from people trying to scam them with the "can we use a cashiers' check" scam. What do you have in your software to keep this from happening to sellers?

[juven14]

I just post a scam warning - i think it would be near impossible to catch these emails if you allow anyone to use the contact form. If you allow only memebers then you can ban any who get reported as being shady. But most people don't want to signup just to contact a seller, so I just stuck with the warning.

I'd like to see what other members are doing, since I've had 1 reported case of this cashier's check scam myself.

[Blair]

Yeah - scammers are going to use any opportunity to make a buck. Since classifieds sites are used to get the buyer and the seller together, it would be really, really tough to implement some sort of filter to seperate "the wheat from the chaffe".

Until you can identify someone by their IP address, it will continue. (Thanks, AOL!!)

[Maffo]

In general, not on all sites due to clients requests, you need to be registered to email somebody. I have also removed the enter email field so the email is sent with registered email address.

I think spammers and scammers should have nasty sentences served to them, just like our friend saddam.

[civ]

We only allow US-based IPs to use our contact form - you will be able to make modifications such as this as long as you buy the Developer edition.

[Maffo]

Civ, can I ask how you have implemented this?