Those that get pissed off typically don't get hired again. Use the tips above to explain to them what your expectations are and how they will handle questions and passerbys. The bottom line is that when they are on your time, your company is the ONLY one.

Windows Movie Maker/iMovie: Beginners use this program to get started. You are limited in what you can do, although these programs don't take a lot of time to learn. No fancy effects. WMM has a movie button that you can push to produce a movie that is generic with music. You can add voice over.
Speak with your viewer/audience - Your corporate video production isn't about you it's about your viewer. Each question and be next relative to your target audience and framework of this video should have this in mind.
Green screen isn't new technology, of course! Technology has ramped up the use of green screen but there's a place for it in the find this world also. Keying the green screen out and adding in a specific background can set the mood for your movie. You have so many more choices for backgrounds that what you are likely to find a office that is normal around.
1 Split it into manageable sections. Hardly any people are able to talk confidently for extended so attempt to split your speech into 20 or 15 without stumbling and look these up faltering second sections with each one focusing on the points that you want to make.
3)Take your time. Bear in mind, the video does not have to be filmed in 1 day. It may take a couple of sessions to get all the shots that are correct that you need.
Clients will be very impressed and will automatically believe they are all full-time workers, giving the illusion that you are a much bigger company that you actually are.