[Ancient]

Well, when a person is planting a bomb, there is usually a few other people to guard him/her. However, since their isn't a guard/squad function, the bot can't really tell if they are safe enough to take the 10 seconds to plant the bomb.
In some instances, rouge players will plant a bomb even if they see the enemy, however, in many instances players wil switch weapons and defend themselves, so it is basicly a 50/50 shot with planting.

With defusing, I believe the bot should ignore their surroundings and defuse the bomb. If a bot could scan the immediate area around him to see if another bot is present, then the bot should go full force with the defusing since he is being guarded.
But with defusing, I would only say to not allow the bot to quit defusing if the bomb is atleast 50% done being defused. (Hopefully that is an understandable scentence, it seems fine to me, but yet it bugs me that multi-lingual people might not understand).