Is there any evidence to suggest that the routing rules are any different from the standard routing rules for a given city-pair?

I'd suggest the following: go most of the way through a booking and you'll get the rules (before you enter the credit-card number). That'll tell you the booking class. Then go to Expedia and get the routing rules for the cheapest fare listed, or ideally one in the same booking class. (Yes, it's still available at Expedia: you just have to go via the site map) If the route you want is permitted by that routing and if Galileo shows you class availability on the flights you want, try booking those flights on aa.com and see if the NetSAAver fare appears. There's a good chance it will, but don't quote me