If the Aliens are landing in person, taking people into spaceships, performing surgeries and then delivering them back to Earth all so they can track and monitor them, then they're doing it very wrong. They ought to have the technology to make use of micro-scale machines to enter into rooms and invade people's bodies (relatively) undetectably. There is zero reason for them to land or perform surgery in person, let alone have a team of them looking menacing surrounding people and operating machinery specifically designed to scare people with surgical phobias. Also note that the conception of what aliens look and act like seems to be rooted in early to mid 20th century Science Fiction, while the implications of emerging technologies seem to point to a far stranger future for us that is far less conducive to pulp SF space opera type settings.
But really, there is a broader issue here.
Since we are summoning hypothetical motivations for things that may or may not be real, it's very easy to make ad-hoc rationalizations for any specific behavior reported by people. In the same way, any and all objections to the Aliens ability to do anything (i.e. hover over ground completely undetected, erase memories, FTL travel) gets handwaved by the vague utterances about advanced technology. Where our science explicitly forbids something they say that they have discovered some new science that our puny earth brains can't comprehend yet. Argument is therefore irrelevant because the claims they are making are essentially unfalsifiable. The Aliens can come here undetected, they can destroy all evidence except when they decide to leave memories in tact for some reason, they can use magic tech to overcome any obstacle to them getting here or doing the things we claim they can do. Any behavior whose motivations are unclear are rational, we just don't know why. And depending on who you ask, there is also one or more conspiracies dedicated to destroying any evidence that may exist and suppressing witnesses.
Broader issues can be a distraction. And this thread is a bit of thinking fun.
Anyway, I didn't say they were doing surgery. I used that as an example of what the unreliable narrator, the experiencer could relate or believe themselves to have gone through. What actually happened? Anybody's guess. And whether or not it's simpler or more appropriate for them to use nanomachines(heh) instead of handwavy levitation, really assumes way too much from the little that we (don't) know. (Like assuming they aren't using nano.) Maybe they don't have enough fairy dust they can blow into your open window and magically absorb all the data they need. Maybe they do but see it as a waste of resources when they can just haul someone in, as it seems to be easy enough for them to do. And it seems they don't worry much about stealth either, seeing how that's been handled well enough for the primitive hu-mans.
There is zero reason for them not to land, if it suits them. There's nothing saying that they even have to land. Many of the stories say they don't. At this point we're second guessing imaginary alien technology,
and it feels good. Just because something "makes sense" according to our new present understanding doesn't make it conform to alien logic. Maybe they have a set procedure about these things. Maybe they just don't have an app for that, and don't need one because what they do works just fine?
And again we're not trying to explain (or debunk) the entire alien issue here, just by examining and discussing one small (mostly hypothetical) facet. Well...some of us aren't. If you want to say that it's all figments brought on by too many root beers, 1950's bomb scares, and movies about little green men, I'll just remind you that Gort and the green cabbage headed martians don't very much resemble grey aliens. Or even the many varied other types that people around the world have said they have seen. These aliens are decidedly, very un-movie like.
and back to broader issues, yes, because the hypothetical situation is an encounter with a hyper-advanced civilization, we will just have to accept the possibility of them being able to do things that we don't understand. That's not an impossibility, and instead of treating it like it is, we should learn to think within that box for thought experiments like these. Within logical "reason", so lets try to preserve some linearity. We don't invent magic, but don't be afraid to pull out a question mark and move on.
your fellow humans are capable of coming and going undetected, they're capable of noticing any tracks left behind and obliterating them, and they can even befuddle a person and obscure or inhibit their memories with drugs. Aliens have only been reported of being able to do the same, and that needn't be attributed to any magic tech, just unknown methods. The point isn't to rationalize or accept every point of every story, or even the concept of "alien abduction" over all. The point is to consider, and only consider, the possibility that something we can't explain happened to these people, and to question what that means. And since these things always seem to come down to FTL... You don't stop on market square on your way to the ball and say "we can't figure this bit out, so it's all bunk". Just assume they figured out how to get here, handwavey style and move on. You don't have to sign anything.
