A number of my relatives are believers in "Smoleńsk assassination", and just over the last few days I've heard them asking questions like:

* so why did Tusk (the PM conflicted with President) even allow them to fly? (false)
* so why did they give away the investigation to Russians? (false)
* so why didn't Russia return the wreck? (true)

...all of which they perceive as evidence that the three official investigations were rigged, and the plane somehow magically flew itself into the ground.