what is your opion;  should cameras be allowed on site? excluding industrial, goverment sites 

can it be used as a learning tool,  help explain why setting up a 32m took an hour to dispatch,  see where an accident may have started...

or is it an annoyans, such as cell phones?

I take a few pics with my phone of every set up I do. I keep them for a week or so then delete them. Just in case any questions from my boss or complaints from customer. Havent had to use them yet but its a cheap ,quick and easy way to cover my arse.

EVIDENCE!!

If you have cameras on a job site, you should designate someone to be a "cameraman" instead of a foreman or a worker on the job.  The sole purpose of that "cameraman is documentation.

This way, someone that should be paying attention to more important things is not fooling around with a camera.

Just my opinion, but I think cameras can be a good thing on a job site.