Just to clarify I wasn't trying to take anything away from Philly's original points but my first comment was in responses to Catrina_ about why the team called them a "bob the builder".
All new players of the game rely too heavily on walls (and auto turrets) "keeping the enemy out" and I was letting them know how hopeless that kind of thinking is since nothing you build is going to last long enough keep the other team from that.
Plus most loadouts AND maps don't favor any kind of "fort" for keeping the enemy out or in.
Sure if the loadout is more ground based and there is room near the flag to build a proper "mouse trap" then it can help but then you just have players that build a bunch of spawn beacons close enough to just drop in and steal the flag anyway.
I strongly suggest to anyone that will listen that forts don't win games. Having good "live" defenders and some well placed mines, not just on the flag platform, but near the exits of your home base is a much wiser strategy.
Not that the whole team needs to camp the home base. But staying watchful of the flag grabbers and making sure they don't make it far once they do grab your flag.
Because unless you're up against a team of campers and flyers that never make a run for your flag, they will take you flag, walls or not, sometime during a game.
And to repeat this yet again, there is too few building slots for fancy forts. If you are on a team with more than six walls built, you are likely on the losing team.
Before this topic gets too many pages back I wanted to add one thing.
Like Philly said, "Walls can be useful".
If new players wants to see how and when to use walls I would highly recommend watching some live feeds of Starhawk's game play on UgentFury (mostly the clan battles).
Most of what I have seen in the clan battles show when and how walls should be used.
On some maps, forts work great and others the clans never really bother with walls and it is wise to know why they do this.
I guess my biggest "pooh pooh" on the heavy dependency on walls comes from seeing new players spending all their time and the teams building slots on building forts and still going 0-5 in CTF because the don't know any better.
Know your loadouts and know how, and more importantly, "when" to build walls. Watch your teams available building slots before you build anything. Leave some open for your team's flag carriers. Clean up your base when you have more than one or two of something. Reclaim your teams "in the middle of nowhere" stuff like garages that are not near an Outpost.
Watch how the successful clans are using walls, repair arms and turrets and you will help your team, not hurt them, and defend the flag and your base better.
Again, thanks Philly for trying to teach that walls can be useful.
I just want the "Bob the builder" on my team to have a proper building permit. 
I use walls as a building deterrent. On orbital, I'll use them to take up space on the floating platform on the side of the enemies spawn. I pepper them around the enemy spawn to stop them from building.
I do the same thing on outlands, I build them on those plateaus around the enemy spawn. If people want to camp under a bubble shield, they have to take out my walls first.
