I am one of the cavs that genuinely feel bad if I bump someone and, even worse, cause him to die because of it. I apologize immediately after, usually even if some people hit M because I cannot be sure if they saw my bump as intentional or not.
Cav for me has a support function in battles, at least considering the lack of teamwork among cavs. If cav would actually form up together and concentrate on targets, they could tear apart fighting lines and flank formations successfully.
Being it is as it is right now where every cav fights for itself, you need to rely on the right opportunities to strike. Often this consists of attacking an enemy that is already engaged in a fight from the side or rear or hunting down oblivious flankers or stragglers.
Where I really try to help is if I see a teammate that is segregated from the group being overwhelmed by multiple enemies. It provides me with great joy to try and get at least some of the attackers off of him to give him a fighting chance or even defeat them together. Unfortunately as often as it works, it also gets me killed or sometimes the friendly guy steps in the way if my charge at the wrong moment and gets bumped and killed.
I think most people appreciate the help, if they realize it for what it is. Some people won't realize the intent to help though, because they are preoccupied with defending their ass, so the best intentions sometimes get unrewarded and I get reported.
But hey, that is part of the game and these challenges are what makes you better as a cav player.
