The original tracks come by a variety of different methods, ranging from radio stations or music journos getting promo copies to fans being vigilant.
The latter seems to be more applicable here with some stupidity on the behalf of one band member, namely – Bono himself.
Apparently he was playing the new album rather too loudly at his home when someone passing outside overheard and recorded it. Yep, it was as simple as that.
Gone are the days of intercepting couriers, haranguing PR people telling them you’re from the NME. Just hang around outside the home of someone with a big ego and press record on your digital recorder.