In this case your punishment is twice as bad as the scammers. If you want to reduce the punishment that you feel, you can only do it by giving in to the scammer and allowing him to win.
Not necessary. All you need is just to proclaim in advance, that
you will always punish the scammer, and be tough. I do not think that after that, you will find someone who will check you out... The scammers will always try to find a less risky options.
This is how psychology works.