....
So there are allegedly burning towns in the count's lands? And, you'd like to take a small army into his lands to deal with it?
Tell me again how giving the count who is actively trying to kill us a reason to say we're invading him is good?
....
You wanna act until somebody can cite some literal medieval law to stop you? How about common sense, because what the law is and what the count will do are probably two different things, and I'm pretty sure the duke can't bring us back from the dead. This count bastard is actively gunning for us, has sent assassins, tried to screw us out of everything we own, tried to get us killed and make it look like a jousting accident, murdered his co conspirators against us when they got inconvenient for him (wool merchant), and a host of other things. Let's not forget he has way more troops than we do and is way better equipped to deal with this than we are.
You think he's above planting a false rumor or two and letting us hear about it through the grapevine so we act upon it and get put in a compromising position?
Maybe it's actually big enough to the point where we can't handle it alone anyhow, so why are we considering acting unilaterally
Recon; gather allies; inform all proper parties (the duke, the count and our allies); go with a joint force.
Need more info, need more help, then act. There's no reason to go alone and then our friends make it so we don't have to go alone.
Going alone is potentially dangerous and makes it easier for the count to paint us as a lone rebellious underling who doesn't know his place. If three lords were to go instead of one, then that crap would be harder for the count to pull off. Do we even have quick response units?
Care about the actual people displaced by this travesty? Offer them safe haven. I find it odd how rarely that gets mentioned. Tactically, what a great way to get loyal followers. Morally, what a great thing to do.