While I personally don't use laser pointers on tours, many of our docents do. I believe the color difference has more to do with the range and "tightness" of the beam, rather than any other properties. It's not really a problem artifact-wise. However, we've had to implement policies about NOT using the pointers directly on people or on work they are doing. I once had to get a docent dismissed because he repeatedly – after warnings – used his laser pointer not only on me and my colleagues, but on our hands and the work we were doing at eye level. (At the time, we were working in public view.)
I'll also note that some people need to actively practice aiming with their pointer. We've had docents whose light waves about wildly, which at best isn't helpful for the tour, and at worst distracting to others working and touring nearby.
I strongly recommend having written policies that anyone using a pointer must review and agree to. They should include things like not pointing at people/living things (well, I guess plants are OK), not pointing into an area where someone is actively working or moving, and other safety tips. Also, strongly recommend "target practice" with their pointers prior to touring.
Jeannie C. Whited (she/her)
Museum Specialist, Collections Division
National Air and Space Museum
14390 Air and Space Musem Pkwy
Chantilly, VA 20151
703-572-4002 whitedj@si.edu