Like may of the contributors above, I'm a bit dubious about what constitues "oral tradition" and where you can draw a line between older and more modern methods of passing on songs. I'm not spoiling for an argument here, I'm genuinely puzzled byt the categories used.
The Copper family songs, for instance, include Victorian parlour ballads, songs with known composers, and broadside ballads that would at some point in the past have been available in a published form. It's quite possible that the older generations who passed on these songs had acquired some of them from printed sources (which I think is perfectly normal and natural for people who are literate). Other "source" singers, too, sing songs which have in the past been published in books or broadsheets, so there isn't necessarily a continous line of oral transmission.
Some of the Copper songs, certainly, were sung in a working environment, but many were sung in the local pub or at parties and private homes. We still use our songs in very similar ways today, with the exception of work songs, and we often learn them from each other in these informal settings.
What I don't really understand is why some people regard songs that were collected by, say, the mid-twentieth century as original "sources" and their singers as "source" singers, and put them in a separate category from modern singers.
Many, many people sing songs that they've never seen written down, or certainly never seen the notation for - in fact, many modern singers can't read staff notation. If you had to decide where you'd learned The Wild Rover, for instance, wouldn't most people just say they'd learned it from repeated hearing in pubs, parties etc? Few would point to a particular textbook or recorded version. I can't see how that can not be regarded as oral tradition.
The big difference today, of course, is that we all have access to recorded music and the internet, as well as a big selection of concerts, festivals etc where we can hear songs (old and new) performed. This accessibility is something to value and celebrate, so let's not regard it as necessariy inferior to the older methods of transmission, which are also still very much in use today.
I'd like to see less of a distinction made between "source" singers" and those who carry on the tradition now, including both the "revival" singers and the younger singers who continue, using any or all the methods at their disposal, to cherish and pass on our musical heritage .