Pity you're a Reb, there's an excellent thread about it at the Quarter Masters Depot.
Here's what I posted there:
As I understand it you need to stipulate in advance whether you will allow it or not.
I know it is frowned on unless necessary, ie you have positioned yourself across a bridge or in a town such that the only way your opponent can reasonably get at you is to melee in column. In those cases it is acceptable, otherwise etiquette and historicity requires that you go into line before the assault.
And of course there is accidental meetings too - a unit in column with every reasonable expectation of unimpeded movement (ie behind the lines or some such) bumps into a hidden unit. In these cases I think allowing the melee is acceptable as well.
... and a follow up clarification ...
But it's hard to make a hard and fast rule here. IF you can change formation before assaulting without disrupting, say on the edge of the terrain in question, then you should do so even though you are moving through disrupting terrain.
It would not be acceptable to move through an abatis in column and asault in column even though you could have changed formation (hard to say why you would want to anyway, there are -ve mods for assaulting in column).
Less clear is what you do if you can complete such an assault in one turn by staying in column formation, but it would require two turns (hence another round or two of fire, possibly from close range arty) if you changed formation.
Real life has no such discontinuities. I suspect purists would insist on changing formation if at all possible, while others may be more leniant.
Another issue is the flanking column and the realities of LOS limitations in our games. If you have sent a flanking column around the back way, at what point would you historically change formation for the assault? Do you allow melee if units run into something they could not see? Even if historically they would have seen the unit and deployed?
And what do you do if your lead unit on such a march runs into someone? Is he stuck assaulting alone? or are following units allowed to come up in column as well. I'd say no, they have to change formation, but that's me.
What about running a unit in column up to cut off retreat? They don't join the melee, but it's still gamey as hell.
And so on. The point is it's a good idea to lay out what you expect in your matchs right up front with your opponent. If you differ, negotiate the difference. If you can't agree, move on. It's an easier discussion when the issue is whether to play rather than who is going to win.
Hope that helps [:D]
Maj Gen Mike Kaulbars
3rd "Freiheit" Division
VIII/AoS
