Know-How Exchange : Advertising/PR

I am not an attorney, and this is not legal advice.

I would prepare a simple release form and ask your subjects if they'd be OK with your using the image or video for demonstration purposes. If yes, have them sign the form. If not, thank them and don't use them.

Can you imagine how annoyed your client would be if you used a customer's (or a prospective customer's) image and got a complaint from that person because they were surprised to see themselves on a website or in a video online?

I wouldn't take that risk regardless of the legality of it. If you explain how the image or video will be used and they opt-out, you should respect their preference. Only use it with their explicit agreement after they understand what it is you plan to show and where.

One possible way to encourage the opt-in would be to offer an incentive of some kind. If you offer something worth, say, $100 you might get more people to agree.

Like Michael, I'm not an attorney and this is not legal advice.

I'm assuming your booth is in a trade show. If so, is there a statement that attendees sign or is somehow stated that "recordings will be taken and images used" for the trade show itself? If so, then as a minimum, get a release from the trade show itself (granting you permission for images). That should grant you the permission you seek.