Re: Why no cloister bell in pandorica opens / big bang?
I think the more important thing is, why did River go through the whole Charade of going to Amy's house and looking at all the Roman stuff, when she knew full well Rory was her Dad, and had already seen him dressed as the Centurion?
Did she? Amy forgot him when he was erased from time, why wouldn't his daughter?
Of course, Moffat offered the more lazy explanation that she was just pretending to prevent spoilers.
And the sign said, "Long haired freaky people need not apply..."