As it 'appens...during the no more than two or three minutes between 'setting up' and the final act, probably three or four people came up to engage me in discussion about what I was up to...no-one asked me for papers or anything, but I'm pretty sure they were looking to see how I responded/whether I sounded plausible or dodgy. Altogether quite reassuring (tho' I was, it has to be said, on the main drag...right outside the front entrance to the leisure centre, with a stream of people going in & out).