Every now and then I reluctantly dip a toe into the GameFAQs Message Board for Metroid Hunters. I say reluctantly because it's a seething hive of vicious junior high students in there, and the air is thick with ignorance and bile. But I persist because I am the only one who cares about you. And that's why I can mention this little tidbit: over the weekend, the kids figured out a glitch in the nickname code. Using the % character, followed by random characters, produces random strings of code with the possibility of crashing and corrupting not only your game, but likewise anyone who connects to you and sees the nickname. The message board monsters were mystified. Having a bit more background in coding, it sounds like a kind of memory leak to me, where using % is somehow directing a pointer to another place in the ROM. I'm guessing this because people not only get random gibberish, but also strings from the game like "Alt Form: Halfturret."
It's a Bad Thing, and Nintendo almost immediately fixed it by banning anyone from logging on if their nickname contains the bug-inducing character. So you are safe for now. Regardless, I don't want to fear-monger, but let's point out once again that the Internet is a wild place, and increasingly consoles are connected to it. It's not like games self-select for a mature and considerate population.