Perhaps "intrusive" rather than "harassing". Strongly discouraging intrusive photography in general wouldn't hurt, IMO. There are lots of people who take photos at free software conferences, and generally this is good because it forms part of our group memory. However, there's a small minority who shove a camera almost into your face and take close-up shots without bothering to ask first, and it can be very uncomfortable. If it bothers me as a fairly confident white male, I'm sure it's much worse for many others.