The OMWF Whodunit

[doublemeat]

Thesis: Xander did not actually summon Sweet in OMWF, Dawn did. (Inspired by discussion on the TVTropes WMG page - the second comment under this heading is mine.)

Evidence:

• Xander is a terrible liar. This had long been established on the show -- see the Xander/Willow arc in early S3, for example. So how's he able to be so convincingly clueless for the entire episode, even while singing under the influence of a spell that compels truthfulness?
• Xander is an adult with long exposure to the supernatural and an almost universally negative view of it. He's the last character on the series who would call up a demon on a whim.
• Xander would not knowingly put innocents in danger, especially his friends. I have little liking for him overall, but even I have to admit that would be completely out of character. Yet, if we believe his confession at the end, that's exactly what he did -- after he knew people were dying, he still deliberately kept his closest friends and his fiancée in the dark.
• There are no repercussions to his supposed deception, which should have, at the very least, greatly upset the other Scoobies and left him wracked with guilt. Instead, the matter is completely dropped and we never, ever hear about it again.

• Dawn is a kid who tends not to take vampires and demons seriously (at this point in the series). She's also desperate for attention. It's plausible that she would have summoned Sweet because she thought everyone was ignoring her and shutting her out.
• Dawn is visibly nervous when she asks Tara if the gang have figured out who's responsible. She only sings two lines in that scene, which are implied to be about her stealing but could just as easily apply to Sweet.
• When Dawn and Sweet are alone together and he accuses her of having "called [him] down", Dawn doesn't deny it. She only contradicts him when everyone else, including her sister, is there.
• Neither Dawn's denial nor Xander's confession are sung. A major, plot-critical point of the episode is that song is more trustworthy than speech.
• Sweet thinks Dawn did it. What possible reason would he have for thinking that, other than the summoning spell itself telling him who cast it? Remember, he has no idea who anyone in Sunnydale is when he arrives.

So why does Xander confess, if he wasn't responsible? Simple -- he realizes Sweet won't leave without his "bride", so he quickly improvises a cover story (something he is, at least occasionally, good at). Most likely Sweet knows the truth, but Xander provides him with a face-saving way to get out of town without having to fight the Slayer. Like Pepe LePew, he's a lov-air, not a fight-air. He's happy to take off with a couple of verbal parting jabs. Do the others find out the truth? Yes -- Xander tells them off-camera, and while Buffy is devastated (which helps explain her continued mental deterioration in S6), they are inclined to forgive Dawn yet another youthful indiscretion; life goes on.

Yes, I really believe this. There are just too many things about Xander's confession that don't fit. Anyone else?