I agree with your punishment (and rationale for it) of Vernon & Petunia. Having worked as a psychiatrist in a state prison system, I can validate that, in the US, at least, neither Vernon nor Petunia would have survived long once their crimes were made known (which they ALWAYS are). This punishment makes THEM 'freaks' on Privet Drive--how fitting!
Oh, and if Vernon is Rumpole, then that would make Petunia 'She Who Must Be Obeyed'! urgh....
Author's response
Precisely what I was trying to put across. This way, hei punishemt will last until he shows real remorse!
And how likely is that?
'She Who Must Be Obeyed'! (Snicker!)
Alorkin