Sure! But a screenshot is trivial to forge anyway, and even if you block PrScrn, people can always taddle. The goal is to get the message safely to the recipien

Sure! But a screenshot is trivial to forge anyway, and even if you block PrScrn, people can always taddle. The goal is to get the message safely to the recipient, not prevent the recipient from disclosing anything afterwards. (Non-repudiation is a common goal, but screenshots being easy to forge solves that.)