To be far, the blade spirits might have been Mat and me. RSB's rules of engagement are far more lax than some of the other RP guilds. We use whatever 7 skills we feel like, and we use mounts. We're willing to change up how we engage other RPers, depending on the event and if the event host has set specific rules, but by and large, we do the "anything goes, all's fair" routine.
I don't specifically remember casting a BS myself, and I don't know for sure that Mat did, but it's entirely possible that it happened.
I really think the big misunderstanding here comes from the fact that, rather or not you guys were actually trying to RP, or just wanted some fun fights, the RP community didn't know what your intentions were, so they responded poorly. I'm sure most of us would have been happy to avoid the res killing, or any other underhanded tactics that went out, if we'd had a more clear understanding of your intentions. For instance, had we known that you guys weren't there to cause grief, Mat and I would have likely looted one or two of your regs (pearl and silk, maybe) and some bandages, to keep you out of the fight, and then left you alone.
Without that though, you're likely to get what we had at the orc fort: two angry mobs throwing rocks at each other. Which is fun too, heh.