I am finding myself greatly tempted to "defile" a library copy of LIAGB. Should I do it and enlighten all further readers or should I not, since technically it is not my property? If I do I am planning on putting the official upgrade sticker. But I don't know. I keep asking myself What Would Jasper Do...but I am not sure if that is the right question to ask.

I'm not sure what Jasper would do, but for myself I would prefer when reading a library book to catch (or try to catch) any errors myself. Not that I'm good at it, but I'd still rather do that than read a copy someone's already "updated" with things crossed out and fixed in the text. However, I would have no objection to seeing an upgrade sticker on the book even if it had not been "updated". Better be careful, though; if your library is anything like mine, they'll inspect the book very carefully and fine you for every little thing they can find.

Welcome to the fforum, by the way!