I am sure this issue has been thought about but I haven't seen a joint answer. We all know that there are a large amount of British regiments than Zulu ones, so when an event is up and all the sides join it's going to be terribly imbalanced. In order to deal with this I've heard people saying some regiments wil join the Zulu side in order to balance, but the thing is, wouldn't that be unfair to the ones that have to join the Zulu side? They most likely don't want to be on the Zulu side. My suggestion is to have some regiments join the Zulu side during the events, but then have the names of the regiments that joined the Zulu side written down, so when the next event comes to town they won't be switche to the Zulu side, the ones who haven't Been written down will, and then the cycle repeats.
The reason this is a topic is I want to see what the developers rink of this and what the other players think would be good balancing.