usual way is they send you a cheque for £xxxx too much and ask you to pay the shipper the extra ( or something like that) you bank the cheque - it clears - you pay them the excess and .. .weeks later the original cheque is returned and bank claws back the funds leaving you out of pocket.
a change in the banking laws recently means they can only take back the money within a few days, i posted this on my own forum and (i think) on here at the time.
maybe an end to money laundering scams at last... I've mentioned it before but bears bringing up again - there was a change in the law this year - banks have had to tighten up their act with cheque clearance or bear the loss themselves.
http://www.gotelee.com/news_det.asp?id=3055
even better - its called the 2-4-6 rule.. interest paid after 2 days, you can draw against it after 4 days and after 6 days it cannot be withdrawn if found to be fraudulent unless the customer ( of the bank) has colluded in the fraud.
Of course if its a huge loss and someone has accepted a £10000 for a painting of say - £200, then I would think the bank is going to try a test argument to say the customer is at fault for accepting it and try to get that counted as collusion maybe? I don't know - but on the surface it seems like good news for us.