What annoys me are people that think VAC didn't work well because MW2 never had dedicated servers. Well duh, the reason games with dedicated servers has less cheaters is because server admins are banning more of them. But even that fails without a way to easily share bans. A cheater joins a VAC server, you ban him then he joins another server and cheats again. No real punishment while his cheat is undetected from VAC.
Also Homefront has dedicated servers and look how that ended up. VAC doesn't change because they move from P2P to dedicated servers.
If Tripwire can use VAC and PB then no reasons others can't. Best of both worlds.