Sorry for bringing this question up again, but i read something last night that i've never seen before.
I found a section in the rules that suggests Bretonnian Knights, and anything else that has to charge also has to advance.
Page 44, bottom left, just under the illustration of the empire knights..... "A victorious unit does not have to advance if the player doesn't want it to unless the unit is normally obliged to charge enemies where possible because of a special rule, in which case it must."
So, (unless this has been changed with an FAQ) that means Bretonnian knights always have to advance. Same goes for witch elves, flagellants....
Also if an ogre unit wipes out a unit of empire halberdiers and there's another one within 5cm. The ogres have to advance into them. (or any other human unit)
What do you think?