I have been thinking a bit on this, given part of my literary work touches upon sci-fi. I am of the view that it is less likely that IF aliens are here, they are directly interacting with humans (including deliberate abduction or other scientifically-tied actions).
I think that mainly because:
1) Assuming the alien species is capable of some degree of direct interaction (which would mean they can at least use language or limbs or material movement etc), and assuming they are an advanced species compared to us, they are more likely to be here to mine stuff they need, and not to relocate power/resources so as to bother studying a much lesser species. Human scientists don't relocate resources in the quest to morph into guinea pigs or otherwise interact with the lab animals in a direct manner.
2) If the aliens are so massively advanced that our human world can be run/examined as something analogously trivial as our own human experiments on lab animals, then it likely follows they don't have anything of note to gain by studying us in the first place. A child may play with an ant-nest, but the ant-nest from the human perspective is just a creation on a pile of sand/dirt.
3) If the aliens are not even similar to some manner to us (eg 3d-based species), then it becomes even more unlikely they would want to observe us, or at least identify us as something 'alive' as they are. Much like we don't tend to view a rock or a sound wave as 'alive' in this sense, despite being able to observe them.
4) Mining stuff can always make sense, and it would not be far-fetched that if some aliens were here to mine things, they would want to be mindful of humans in the area they are mining, and thus react if their business was threatened, including in violent fashion.
Anyway, just to - hopefully - get a discussion going. What is your view?