If Google thinks two sites have a relationship (i.e. have the same owner), will links between those two sites...
A.) Be devalued/discounted and not pass Toolbar pagerank or true pagerank.
B.) Be devalued/discounted and pass Toolbar pagerank, but not true pagerank. (to confuse link spammers)
C.) May or may not be devalued/discounted, and pass Toolbar and true pagerank based on the decision to devalued/discounted.
What I'm getting at is, if the same owner has two sites that link together, and there is a TBPR increase from those links, does that mean that Google either doesn't know, or doesn't care if the sites are owned by the same person.