Well, I'm pleased my idea has some merit. Unfortunately, we can't conduct anything approaching a scientific experiment, as we don't know actually how many of these trolls there are, so we won't be able to tell if amending the registration agreement has any effect.
But, amending it would be simple and quick, so what is there to lose by doing it?
Agamemnon, you're right that many Christians lie for God, and like Venomfangx they will continue to do so. But I still think that some Christians would baulk at lying on oath - in exactly the same way that many atheists may tell lies, but would think twice about lying on oath, for example in court - which is a crime, after all.
Looking at my wording again, I would suggest a change. Instead of:
If you are a Christian, you swear by Almighty God that you are not registering with this forum for the sole purpose of fulfilling an academic requirement.
... I'd replace
by Almighty God with
on your deity's name. First, because we're agnostics so we don't use capitalized proper names for imaginary beings; second, because using the word "name" echoes the Commandment which we are invoking:
You shall not take the name of the Lord your God in vain.
Gnu.
PS. I have been maligning Smartnoodles, by the way - she has returned to continue her thread. Apologies to her. (But Breckmin still seems a viable candidate.)