"Didn't MacColl also sing with his eyes closed?"
No hard and fast rule - he sang with eyes closed on some of his quieter songs, but on is humourous or more outging songs, not always.
He stressed the importance of eye contact with the audience as a regular part of the performance as a method of 'including them' in his songs, but as he also argued for varying your type of song in order to keep 'the listeners ear working' (big thing with him) you always got a bit of both in his performances
Jim Carroll