I would think that the technology they would have could easily disable or scramble anything in a certain radius, just speculation. They obviously aren't stupid, and when burglers want to brake into someone's home they clearly scope the place out. I worked in a plumbing merchants for over a year, and we had a LOT of copper piping. I came in to see police vans and blue lights going and my boss telling me all the copper was gone. When I watched the CCTV they knew exactly where to hit the cameras and what angles they wouldn't be seen. If you done that on a larger scale with aliens supposedly so much more advanced, CCTV becomes irrelevant.
What does bug me though is the amount of decent phones people have today in their pockets and the crappy UFO videos we still keep seeing. Now I have done some astrophotography with my dslr, ISO needs to be rather high, on cell phones the ISO isn't that good, but even at night it will look grainy even on a dslr at times depending on how high you have it. In the daytime however the phone I'm using is astounding, digital zoom unfortunately like most cell phones.
You seriously telling me Betty Hill claims to have a flying cat ? What age was she when she said this ? Maybe the only thing flying at the time was her mind. As for Travis Walton which I totally forgot about, his case is extremely interesting too. Would love to see a remake of his movie, the film wasn't exactly accurate to his actual story. I listened to him on the Paracast a while back, I think he was doing some event in the town he was found. I wouldn't dismiss Betty Hill's case though on something she said much later in life, but if she said this in her younger years not long after what happened then of course I would be skeptical, it would show she has a very wondering imagination. But as you get much older the mind can certainly make you say silly stuff. But If I had to pick between both cases I would go with walton based on the fact he hasn't altered his story or came out with crazy stories.