I got up this morning with this still on my mind and for two good reasons:
These will be the same people who say the event wasn't good and shouldn't be sponsored again.
If random photos were taken and the client/partner/sponsor saw the photo it ruins the reputation of not only the brand ambassadors but the event organizer.
When I normally see vendors or staff sitting around, as an event organizer, I ask them questions. Some of the questions I ask are: "How's the attendance at your table? How many people have walked to your booth?, Is there a give away or something you'd like attendees to know about that you've considered that I didn't know about," and other questions. If I walk back around the event and continue to see them sitting around, I take random photos. Why? Well, it's been my experience that when they get back to their office and their boss says how was the event, they quickly say, "It was horrible or our demographic wasn't there or anything that that might place the blame on the event and not them.
Remember that as you walk through your event so that when you do your event follow-up and go back to ask the sponsor to partner with you again you have a leg to stand on.
Yes, it may seem like you're telling on the person/persons they sent but your honesty & integrity will go much further with them and those they refer to you in the future.
What about you and your events? Do you talk to the participants when you see them not doing what they were sent there to do or do you miss the opportunity to engage and assist them? Do you follow up with the client and send photos or do you schedule a meeting to go over event details?