The councils word for "spontaneous interaction" (which sounds filthy anyway) is impromtu. One off such events are allowed.

Of course if you think about this, such things are not a problem, as twenty or so musicians and dancers just coming together by chance (that sounds pretty filthy too), is unlikey and if they choose to do it again, it is then not impromtu and subject to the PEL.

The problem being, if you read my question, is the production of a programme of where the side will be dancing through the year.