droit du seigneur: a new theory

Concerning the Straight Dope column about medieval lords having the right of the “first night” with local maidens, I recently heard an interesting take on the theory.
My sister, who is a Wiccan, claims that stories about the “droit du seigneur” are a distorted account of pre-Christian times, when many pagan cultures had rites where the local virgins were ritually deflowered.
I also vaguely recall something about the Romans having such a rite where maidens would straddle a carved statue of a god. Can anyone supply some more information about this?

Since Arnold Winkelried can’t be here 24/7, I’ll play Swiss Hero for a moment.

The column referred to above can be found online here:
Did medieval lords really have the ‘right of the first night’ with the local brides?

And boy, it is a pip.