Can someone explain to me scamming mechanics?

[yonisimo1]

Just got scammed (Icecrown) by a blood elf pally called *****

He traded me mechano hog and i put 17k

I was sure that if i press the accept trade AFTER he do (and its already green on his side) he cant changed it,

so i didnt bothered to take SS

ofc it didnt matter and after he accept the trade - and i saw te mechano hog in the window- still he got my money and i didnt get anything...

[Thorbjorn]

He changed the Mechano-hog into a key that looks the same. Always check what item it is once he clicks trade and window goes green. Scammers often put Mechano-hog first into the trade window so that when you glance on it it is indeed a mount and then when you type your gold he will change it to a trash drop key item and click "Trade" which makes the window green.
Be more careful next time.
Make sure to read how to report scammers here: http://forum.warmane.com/showthread....=1#post2651921
and for the future always take the screenshots for EVERY trade as it's described in the post. Better safe than sorry.

[yonisimo1]

u r right again - i see in my key bag a "Benedicts key" thats looks the same and wasnt there before...
i saw in the forum that someone recorded him i hope it will help