Thank you all for a very informative thread.
I would like to ask about a somehow related issue: the small balloons with cameras.
This hobby has became popular recently and I wonder to what extent it is safe?
See e.g. the video:
.
In particular, look at:
- 2:32 - to asses the size of the balloon, and
- 3:52 - to note the proximity of the plane.
Is it really scary, or am I a paranoid?