Last Sunday I spoke with an ethnomusicologist and multicultural choir director.
He said that, not so long ago, he had to go around, often far away, with a tape recorder seeking for popular songs.
Now he simply goes upstair and knoks on the door or rings the bell. :)
A little problem: in his compound he met two families of Rumenians and both sung, in theory, the same Rumenian song... but the two version were completely different! :D
I think that's also common when doing field recordings - all around the world.