Starting isn't that important. It's the same reason why House didn't start for Rondo or Posey didn't start for KG two seasons ago. The goal is to mess with the rotations as little as possible. Happens a lot, most NBA coaches follow this philosophy, I don't get the surprise.
Starting Giddens in front of Hudson was important. It tells everyone that Doc has Giddens in front of Hudson. Even though last night, Hudson would have made more sense to start since the team needed a pg.
I don't know, starting Giddens offered the team more defensive balance, has he has the length to guard Turkoglu and allowed Tony Allen to harass the ball-handler. But I agree Giddens is ahead of Hudson in the rotation. I'd be surprised if he wasn't.
I'm not at practice, so I don't get the privelege to see how well people play with no pressure. I do, however, get to watch all the games where pressure can make some good practice players into a bundle of nerves. I also, have a bit of Doc Rivers' talent evaluation history on my side. Examples:
Telfair over Rondo
Scals over Gomes, Powe, and Baby
Lafrentz over Perk and Big AL
Wally over Delonte
Sometimes we see some things months before Doc does. I'm going on record, from what I've seen, that Hudson is the 2nd best pg on our team. Also, from what I've seen, Giddens can't handle the pressure.