"Dear sir, it would seem logical that whatever phenomenon is responsible for affecting batteries can also affect film photography."
So you think I am being naive not to think that if they can tamper with batteries they can do the same with film photography. Well, if we approach this kind of theme with an assumption such as yours, we are bound to find only paranormal explanations.. If you are already assuming that it is an unexplainable phenomena, what kind of down to earth explanation could there be?
My first approach would be to investigate the claims. I think that if one is to investigate this equipment failure theme, before rushing to blame the trickster and write 10 books about it, one needs to be sure it is an actual event and not an invented one. Is it a real event or just bad luck? Are documented events backed with credible proofs? What makes the people that documented it credible? Was there a background check made on those persons? etc.. It's not paranoia, it's basic investigation procedures.
And as ironical as I sounded when asking if there was some kind of a statistic that could prove that people have been having more problems taking pictures than 10-15 years ago, that was a real question. I am really wondering if that is the case and what was the excuse then. I know that analogue or digital cameras can be tampered with, but I'm interested in knowing how was it logged 10-15 years ago. Whatever phenomenon responsible for battery drainage will not necessarily interfere with analogue cameras in the same way, for one because they don't need electrical power to operate and two because common film spectral sensitivity is mostly visible light for which cameras are shielded, so if the cameras were tampered with, what was the end result? what happened? I would assume that to be an important subject to research if someone starts to investigate the equipment failure documented events as Christopher O'brian suggested.
I could be wrong but my opinion is that there isn't any equipment failure. I believe that batteries going dead and magnetic storage failure are a common problem of everyday life and easily accepted as an explanation for not being able to record a supposed extraordinary event. I also believe that paranormal fields such as this one (UFOs) are populated by easily manipulable and gullible people that WANT to believe and when I see or hear about an extraordinary event that is backed up by ill-documented proofs, I know that it is aimed at those people.
I don't believe the trickster entity to exist. I believe in bad luck and good luck, good will and wicked will and I believe in our own personality to be able to interact with life without us to know about, maybe in paranormal ways. In order to believe that the trickster exists, I would have to believe that angels or some other kind of "good fortune advocate" exists as well. I don't. I think humans are very powerfull and complex creatures and credit is far too often given to external forces such as God, Jesus, trickster, miracles, etc... Instead of having faith in something you cannot see and testify, people should believe in humans. Did aliens built the pyramids? come on.. don't underestimate the power of slavery.