Assuming you only wanted to strike an opponent (not a brick, board or block), would you need to condition your hands to avoid injuring them (by accidentally hitting a skull or a jaw)? And if so, to what extent should the hands be conditioned?
(I don't mean you'd condition them by hitting a skull or a jaw -- I mean you might injure them by hitting a skull or jaw accidentally. Hope that's clear. Otherwise that'd be one bad-*** dojo. "Hold still, kid.")
Again teaching by two demensional means book computer is very limited. Theory is what it is the street is fluid changing savage. proper conditioning should help you to be able to take a blow especially in CMA as well as inflict if necessary.
Injury is possible no matter what conditioning. The condition should be such that you can strike hard enough to gain the desired effect with out permenant injury to your self but also I teach my students options or think of the end result of your actions? striking the nose while effecting results in lots of blood and blackend eyes for police and a jury to look at while winding them control grappling escape or even making them unconcious with out side effects is much better for your liabilty let alone. Every situation is different better yet to not be there avoid at all cost if you can't if its a total surprise bad planning on your part you will do what you practice not what someone tells you or read in a book.
The possibilty for you to hurt another person accidently is always a possiblity it is my first concern unles there is 3 or more.
When I travled and trained nation wide I would often go into random training facilities like the two guys on Dicovery channel getting the crap beat out of them to experience different styles and I do not remember the sate or style but mid to East coast and they would train with out shirts bare fist striking differnet parts of the body to condition taking the hit and they trained thier big toes to strike at a person's hip joint to dislocate very hard core.
Just keep in mind you build your body up not tear it down