I was there Friday night as well and I disagree about the 65%. More than half were Nats fans. Maybe it depends where your seats were
Watching the fans come in there was definitely plenty of red shirts and hats, a fine showing by Nats fans. I sat in an area full of season ticket holders so the vast majority were Nats fans. Of course there were also plenty of fans wearing gear for both teams.
The Lets go Yankees chants came from the area by the Nats bullpen where the FO usually sticks the Philly groups, so clearly the Take Back Nats Park policy did not apply to this series. In the competitive portion of the game they were booed down, until Davey crap the bed and put Lidge in.