I hate it when anyone pulls this argument.

[AFTT47]

Even outside the issue of religion, I hated my teachers telling me to read something or watch something blindly without having an idea of what the message was.

If you are not willing to inform me before hand what I am getting into, don't bother. The best cons inside and outside the issue of religion, rely on the mark going in blind.

If your argument is valid, it should not bother you at all giving a summary of it first.

I agree to a point. It does smack of dishonesty and insecurity if you pull that tactic. You should not need to resort to this if you are confident of your position. It is the mark of a poor debater. It does not necessarily negate his or her opinion, however.