I'm not sure I understand your comment. The chucks on hand drills are pretty universally hand tightened. It isn't as though there's a chuck key to tighten it down until the bit screams for mercy :-)

I should probably clarify that you can usually get away with drilling in reverse for a little bit, but if the bit is truly stuck and you start twisting the drill around, you're pretty likely to end up loosening the chuck. Obviously, grabbing by the chuck and trying to twist the bit in reverse is a sure-fire way to loosen the chuck.

Because the crank is geared up, you don't get much torque cranking in reverse, so once you get a bit stuck, it quickly becomes a pain to get it free.

Who is this idiot who keeps getting drill bits stuck, you ask? It's actually pretty easy with some bits. I have a set of DeWalt bits that cuts far too aggressively in softwood. Especially as you're exiting a hole, the cutting edges will feed though without fully clearing the hole, and the remaining wood will engage the flutes and pull the bit in like a screw. This usually also compresses the wood into the flutes as well, and just makes for a real mess.

With an electric drill, you can (if you don't care about the back side of the board) pull backwards on the drill and gun it, and let the edges of the flutes clear (tear out) the bits of wood engaging them. Not really an option with a hand drill.

What I usually do with a hand drill is to pull back and crank normally; the bit comes out easily, pulling back keeps it from going deeper, and it also removes the swarf in the hole cleanly.

Come to think of it - I do this with electric drills, too (and you pretty much have to with a drill press). So now I wonder:

Why is everybody switching their drill in reverse to back out the bit - this shouldn't be necessary!

The only time I've used reverse in an electric drill was when I was using it to drive (remove) screws (variable speed drill of course). I think for certain materials you have to run a standard bit in reverse to drill them properly (for some reason, I'm thinking glass, or ceramic tiles?)...