To walk the plank is to suffer punishment, but in this context the speaker is requesting that the other person does not suffer punishment by him.
Consider the staetement "And as a pirate, I can do none other than humbly request that you not suffer punishment by me.". Based on this statement, is "And as a pirate, I can do none other than humbly request that you walk the plank." a true statement? Yes/no/unknown