in my country Romania, on Orange Ro the MMS limitator is at 100kb, they told us (cc agents ) to tell the customers that an mms bigger than 50kb will not be sent.
You only have to try sending an bigger mms, not exagerating to 6000kb but something around 200-300kb -> a game or app :) maybe if your operator network is not as limited as mine.
The catch is that your friend have to use a pretty good phone that can receive such a big mms.
So, no, this trick is not fake :)