We've confirmed that no one had roach eggs hatch inside their tongue, but - it is absolutely true that given the opportunity roaches eat the glue off of stamps and envelopes.

Hawaii has a lot of roaches and in our first few years of living here we noticed that our envelope glue was disappearing. At some point, we opened the stationary supply drawer to find the little buggers in the act! Needless to say, we use the self-sealing types now. Now, I don't know if other colder places have such a roach problem, but if you've so much as seen a roach in your house I would bet that he'd love to find your stationary supplies and have a sticky snack!