[ppml] Difference between ULA-C and PI

ed said that the situation wasn't well defined and then:

> 2) PI puts a route into the DFZ, the other thing doesn't.

maybe PI puts a route into the DFZ, maybe not.  maybe it puts zero routes
in (fallow) or maybe it puts multiple TE routes in (grazing the commons).

maybe the other thing doesn't put a route into the DFZ, but it could still
put one into the automotive network exchange, or COMMONS, or elsewhere.

> The latter point makes the non-routed address scheme less "costly" to 
> network operations.

maybe.  in fact, double-maybe.

> At least this is what I have gathered from reading the threads on this.

and then again, maybe not.