[spiderbro]

Ok I think I understand your point that XCP-invalid-TX spam cannot be filtered at the point of origin like invalid BTC transactions and a motivated attacker could spam the network to make it extremely slow to use XCP.

I think this is a valid concern, even if somewhat mitigated by the 0.0001 BTC transaction fee. I'll post this to the BTCTalk thread and see if someone smarter than me has an idea to defend against it.