so are we talking product opportunity here?

An Alpha and NNSTAT and GateD running as part of a DAS ring that
otherwise just has an NSP router and a GIGAswitch port, with a
lot of hand tuning to notice "bad" flows, would definitely help
discover "unintended transit" situations. Surely there's got to
be someone on this list who wants to tackle the opportunity to
build and sell such a box.

Wouldn't a cisco SwitchProbe serve basically the same purpose?