Remember people, these weren't collectibles when they were written on, they were just games. Also, these games were expensive for the time. Hell, you paid the same or more for some of them than we do for todays games, and this was 20 some years ago.
I still have my original NES system and all the games I had, and yes, I wrote my name on them all. Because I did not want to get into an argument with my friends if they were borrowed about whose they were.
And someone else said it well, are you a player first or a collector? I am a player first and always will be. But I am also a colletor. But as a player, the fact that someone wrote their name on the cart, or the label is half gone, doesn't affect the playability of the game, which is what I care about first.