#1 'Andromeda strain' I'm sure that scientists will the first to study anything returned from the first mined asteroid.
#2 The asteroid they are returning will weigh less than the ISS and be parked further away. Tackling the control/direction of asteroids is something we want to learn anyway.
#3 We are a long way from strong AI. If strong AI is created, asteroid mining would be the smallest footnote in its capabilities.
#4 There are abundant industrial uses for PGMs so there is a high floor price and continuing demand. Markets have established systems for dealing with periodic resource delivery (futures).
1) Any theoretical space viruses can already get to Earth just fine. We're pretty sure they don't exist though.
2) Yup, a real concern. I'm glad they're starting with a reasonably sized asteroid.
3) An AI rebellion probably won't look like what Hollywood says it will.
4) Awesome! There are so many cool things that you can do with gold and platinum that we don't because they're so damn expensive.
What about:
1) Biological issues (space viruses etc.)
2) Accidents (opps the orbit changed it's heading for Chicago)
3) More AI for robots, Skynet finally has a good resource base
4) "Today in the news global markets failed as PRI announced capturing a 1 billion metric ton astroid with 80% gold and platinum content"
I am actually super excited just thought it was interesting to think about the counter issues.