Okay, so, re: the Marauder’s Map and the fact that legendary pranksters managed to lose it to the cranky old caretaker.
I haven’t seen anyone else mention this yet, but I always felt like the Marauders let Filch confiscate it. Like, it was toward the end of seventh year, they weren’t going to have much use for a map of Hogwarts soon, and they were all eighteen, basically still kids, so they weren’t exactly thinking, “I’m gonna save it and give it to my kid when he/she goes to Hogwarts!”
They don’t want their hard work to go to waste, though, so they decide they’ll pass it on to the next great prankster. But when they look around, they find no one that seems quite right for the job yet. Filch has been insisting for ages that there’s something up with that piece of paper and has never managed to successfully confiscate it since they created it.
But this one last time they let him. They put on a good show, trying to convince him to “Give it back, please!” But he refuses, locking it away. Meanwhile the Marauders walk off with a smile, remembering all the times they’ve snooped through Filch’s office while serving detention.
Someone else will surely do the same, and when they do, they’ll find an otherwise ordinary piece of parchment and wonder why on earth it’s been classified as “highly dangerous.” And when that happens, their legacy will continue.
