Not so many if any of them were working at any of the many companies and institutions that would detected such a thing and had measurements to support it.

A 100 years ago if a few thousand people all swore they saw a flying saucer over Stonehenge it would be rather convincing. Nowadays, such a sighting is impossible to witnesses without the object also being caught on any number of detectors around the globe, so if they don’t support the eyewitnesses I’m inclined to believe the sensors.

But I suspect you've convinced yourself with explanations that the sensors of the Navy around those released UAP videos were somehow invalid, or the many, if you search, nightvision UFO video, are also invalid. it would be cool if humans really had silent anti-gravity triangles, and if people see those or have an experience with them I think it's wrong to say well given that one of the possibly interpretations is aliens therefore this evidence must be discounted in these people must be crazy. I'm not saying you're saying that but I think there's definitely an incorrect trend in that direction

Something interesting about this stuff is that there's not perfect cover across all sensors always. Maybe sometimes you have people seeing something that's not on radar. Or you have something that's on radar but not on other types of sensor. Or you have something that's in the infrared but not in the visible. I'm not asking you to believe anyone interpretation just to be open and consistent I think that if you're willing to believe the sensors are malfunctioning and creating ghost tracks it's also reasonable to consider that the sensors are not capable of picking up some sorts of technology. I understand that depending on your pliers there's different takes have different probabilities to you but I don't think it's okay to rush to certainty and discount any of those interpretations and say that anyone who suggests as much or obvious for those is out and out crazy. that's offensive and abusive to people and not I think in the spirit of investigation and curiosity.

I never said people are crazy.

And I don’t know about the examples you mentioned because I haven’t looked into it.

My point is basically that explaining an anomaly by “visiting aliens” is quite a leap of faith.

I also highly doubt that a credible sighting would not be picked up by the general scientific public.

So given the immense vastness of space and the resulting difficulties in colonising it, I remain unconvinced.

That's good to know, because I find that abusive, and disrespectful to people who are just trying to discuss things. But people on the "believer" side are no better. I'm sorry to seem to falsely accuse you of that, I really wasn't. I'm just sort of waxing in all directions to share my views, taking as a starting point the inspiration from people's comments here. It needed to be said, anyway :P ;) xx

I agree with you that it's a leap of faith. I'm not asking you to make that leap. Seems you have an open mind. All I'm saying is all these experiencer testimonies I think means something is happening.

I'm not sure if by picked up you mean "detected in their telescopes" or "the story picked up and discussed". Case 1 is I think unlikely unless there were sightings everywhere at once. But there have been multiple things seen in the sky over a number of places, like Mexico City, Phoenix, Belgium, etc, that got lots of press, and have videos and hundreds of witnesses. Case 2 I think is a result of stigma. For the same reason that, even tho > 50% of people believe in aliens and psychic abilities, you are not allowed to research into those things, and if you do, people will call you crazy. It's changing a bit now...but

I agree with you on the vastness making it difficult. But I think it's arrogant to say, "Well, it looks difficult. Nah, can't be done." because that assumes that other civilizations would be unlikely to achieve more than us. I think the vastness of space and time, and our civilization's minuteness, is its own counter example to that take. It permits an alternate take which suggests there has to be somebody else out there, and they had plenty of time to do stuff.

In terms of why there's no "open contact" I like to fall back on the Star Trek Prime Directive.

By picked up I meant your Case 2. But I don't believe people are afraid of stigma. I think people in general are very curious about and interested in these kind of news. Think about the Oumuamua coverage. It was a strange thing that had no clear explanation and a remote but exciting possibility that it was an alien ship.

That went all over the world and credible/authoritative people commented on it and the possibility. Of course with all the appropriate caveats and scepticism, but the discussion was had.

About the capabilities of other civilizations, I of course concede there are almost certainly many out there with vastly greater capabilities than us. But space is just so stupidly large. Also what is the chance that aliens happen to make contact just as we as a species started to realise there was more out there than us?

Why isn't there already an alien colony here that was established a 100 million years ago?

That's actually the plot in a sci-fi I'm reading these days so there's that... In addition to the Prime Directive there is also the Dark Forest theory explaining no contact, I quite enjoyed Ken Liu's Three Body Problem trilogy.

I am very excited by our near-term (next 200 years or so) possibilities to colonize the solar system. Rather disappointed I won't get to see it happen barring some major life prologing therapies in the next decades.