I always mail things with trepidation, like sending a kid to summer camp. Sometimes I read “human interest” stories about a letter that was mailed decades ago being found inside a wall, or under a supervisor, or stuck behind some ancient machine at the post office, and then they dutifully track the recipient down, but she married someone else and he ended up joining the Peace Corps, when otherwise they would have gotten married and had a son who would cure cancer.
But I digress. I will mail stuff because it’s cheaper than driving to Teaneck, New Jersey from Washington state, and faster too. Things generally show up intact; maybe the instructions I scrawl on the package help?