What was that business where the audience used to flap their arms about and shout IRA during Fields of Athenry. Do they still do it?

I once heard a wonderful deconstruction of Spancil Hill in a pub in Nottingham.

Last night as I lay dreaming
(What were you dreaming of Paddy?)
of pleasant days gone by
My mind was bent on wandering
(Where did it fly off to Paddy?)
To Ireland it did fly

Perhaps it was just nights I was playing that the audience had to amuse themselves in this fashion, but actually it seemed very well rehearsed. Anyway I enjoyed it - not sure if Martin Carthy and/or Dick Miles would approve.