I'm no expert on ethnics but wouldn't the easiest solution be to ask the users to sign a media release form?
CISCO is making a promotional video/booklet, and at my colledge before we were filmed/photographed we were asked to sign a media release form. On the form were various levels of content exposure to which we agreed to.
e.g. check boxes for
if we agreed to have our photo used on their website
if we agreed to let a video of us 'networking' be played at other colledges
etc.
That way, everyone is aware of what is happening, and you/they are aware of what they have agreed too also.
If anyone doesn't want to participate, they don't have to.
__________________
Last night I lay in bed looking up at the stars in the sky and I thought to myself, where the heck is the ceiling?
I am 75% addicted to Counterstrike.
What about you?