I definitely see your point regarding the possible lack of experience of a given newly-minted instrument pilot, but I dunno about the "100-hr-past-PP" thing; that's a bit extreme. I had something like 10 hours as PIC when I first took up a passenger- looking back, I think I was even more cautious then than I am now (the stats, for what they're worth, indicate that PICs with under 100 hours have an excellent safety record, esp. compared to 200+ hr pilots).
But I made sure I had good wx, picked up my passenger at Princeton,a field I'd never been to, stopped for lunch at Blairstown, a field I hadn't landed at since my Discovery Flight, dropped her off at the other airport, and made my way home without mishap of any kind.
Maybe it helped that I had almost 100 hrs total when I got my PP, I dunno.
