Fred/George
So, they have to process Muggleborns, right? And their notice was REALLY SHORT?
What if we flood the MRC office with "Muggleborn Registration" papers on the day of the deadline to maybe give some Muggleborns a bit more time to put together forgeries or get out of the country before they're pursued. I mean like, bins and bins and bins of the things. Nearly drown them in it. I'm thinking like what Dumbledore did to get Harry his Hogwarts letter, remember that story? Maybe McGonagall knows how he did it. A bunch of obviously made up names but plenty with legitimate looking so if they really want to decipher real from made up they'll have to go through every single one regardless.