There's a line between pulling off a bait-and-switch that amazes and impresses the audience, and pulling one that pisses the ongoing viewers off because it makes them feel cheated. There's been too much of a buildup in the focus on Claire for them to get away with not making her be the cheerleader in question (especially with Isaac's paintings showing her face -- it was Peter's crappy work that made it so non-obvious that the dead cheerleader wasn't Claire, which was actually brilliant in terms of them misleading the audience without breaking the rules).