Borrowing shamelessly from a travel Stack Exchange question https://travel.stackexchange.com/questions/2825/2fabe-the-secret-international-travel-postcard-stamp-code:
I was told about this about three years ago, that if you were desperate and didn't have time to buy stamps for a postcard, merely putting the code '2FABE' would get your postcard to its intended destination.
Sceptical at the time, I searched for it on Google and found nothing. Now searching for it has a couple of people asking if it's real, but no actual answer.
After being in the expatriate community in London for four years, I'd met several people who have tried this, from many countries, and aside from sending from China, word is they've all gotten through.
The obvious question would be 'is it real?' - but that doesn't seem to matter as it seems to work. The real question is WHY does it work? Is it a special code that means something? Is it an informal system like the old 'S2S' (Student to Student) code was meant to do? Or is it just blind luck that these have all made it through.
It came up in tonight's #TTOT (Travel Talk on Twitter), after I mentioned it, but nobody else had heard of it, so figured it might be a good one to ask on here.
One person has posted a suggestion of comparing it against some controls: putting random codes on the postcard, or no codes at all.
Is 2FABE any better than a random code, or no code at all, at getting a postcard sent?