Huh, I only now realized that some envelopes are actually coated with numbers. I knew that they were identifiable to track down both production and point of sale, but I never realized that they were so clearly and obviously numbers
@noiob Yeah the printer thing is what I was mostly thinking off in relation to this, I remember the security scares of the 2000s that lead to everything being trackable by authorities
@praxis if they wanted to make sth trackable they'd make the info less visible, like the yellow dots all color printers put on every page