The thing about the USPS is that despite all of the reagan-esque bullshit that's been done to it, it's still a far more human entity than any of the commercial parcel services. For instance, my office has two different addresses, and to try and figure out which one was actually recognized as the official address of my building I mailed letters to both of them from the local post office, giving myself as the return address. the carrier put them in my box with a rubber band around them and a note telling me not to do that and also what the correct address was.
this is why I cannot stop thinking about the idea of sending a slice of pizza to somebody with media mail, because the post office is authorized to open any media mail they think might not be media and return it to sender, and there's a good chance I would get it back with a note inside that just says "Go fuck yourself dude"
reminds me of the time at my last job a dude brought in a whole ass cake in a box he clearly just bought at the grocery store, and he wanted to mail it to his friend in another state. And I had to very calmly explain that, that's not how anything works - I covered the basics, you know, "your package goes through sorting facilities on conveyer belts, being hit by rubber bumpers and falling up to 10ft into sorting bins, neither the facilities or trucks are air conditioned, and nobody is going to handle the box gently."
He seemed put off by this, and asked me if we could put Fragile and This Side Up stickers on it to make them handle it nicer. I emphasized that this would change nothing, and that I couldn't even pack the cake anyways, I mean what, bubble wrap it? He was very incensed and said "well what am I going to do with this cake? I can't return it!" And it took all of my power to not tell him exactly what he could do with his cake.
So what I'm saying is someone has absolutely tried to send pizza through USPS, and someone has probably succeeded.
fruitcake, like, the firm dense fruitcake that everyone memes aboout how it sucks and such?
the 'modern' fruitcake was in part meant to be sent by mail. fruitcake was something you made at home and mailed to your distant relatives for christmas, or mail ordered for them from a fruitcake bakery. some of those still exist and they still to this day i believe send it by mail.
You can absolutely ship fruitcake by mail. I used to mail friends fudge as long as the weather wasn't too hot.
USPS has extensive lists of what they are absolutely willing to ship and there's some impressive stuff on there, food included. So I just want to be clear that the only problem with my plan was sending it by media mail; Pizza, unfortunately, cannot conceivably be justified as educational materials