Account sharing and multiple cd-keys is a plauge in this strat, i really witnessed lots of situations where was ovious (like 20 people moving as one, or chars with similar names, or people that it's oviously not online and it's just moved by someone else).
I hope you devs will put an end on this soon, but i have doubts you'll manage to stop completely. People are using proxies or just connecting from another house (like 1 char at home 1 at office, or 1 char on pc 1 char on laptop).
I have a private network and when you banned my ip because i put wrong password too many times, i could connect from another pc in the same house without needs to do nothing.
That said, i agree with 3ABP, don't see why we can't play one strat battle with an archer, and the next with an xbowman. It's not that we will help our factions with extra troops or gold, we are just talking about battles.
I think you should allow all chars to do strat battles without any need of buying a second cd-key, or at least add a free respec (like every month or so you can do it without losing half xp).
There will be still a main, so the second chars will not be able to sign for IA fiefs (the only possible exploit i can think of)
If you think that's not an issue and we can just do the respec and loose half of the xp when we want to change classes: I'm level 32, i have 27,874,839 xp and it took almost all summer to go from level 31 to level 32 and half.
I'll never respec, i don't want to lose 15 milions xp just to play 1 strat battle with a different char, and have to do all the grind from 31 to 32 again.
Let us have fun with trying different classes every strat battles, as long as we don't flood strategus map with alts