I wouldn't object to this being included, but flooding attacks on generic targets are kind of a generic Internet threat anyway. I'd want to see text that very explicitly says why this is a threat *made worse* by the presence of multi6.
Right. And I think we have that explanation, it relates to amplification. There's plenty of documents that can be referenced regarding this issue from the threats doc. See for instance draft-ietf-mip6-ro-sec-02.txt Section 3.2.1, draft-vogt-mipv6-credit-based-authorization-00.txt Section 3, Aura et al: "Security of Internet Location Management" (ACSAC), etc.
--Jari