Can be played in a standard pub session setting on typical session instruments, just bring a kazoo. Check.
Slice of life, common folk details in the lyrics. Check.
Music derives from someone's tradition. Check.
Imma calling Paolo Nutini's joyous Pencil Full of Lead as modern trad/folk, even in his original bluesy/jazzy instrumentation, and no one's going to convince me otherwise ;P

Happy to use this to kick off a discussion on what constitutes trad and folk but I'm not changing my mind regarding this gem :D :D :D