What's everybody's take on the manufacturer's stickers that are placed on Walkmans? Would it be completely taboo to pull the sticker off and bin it or maybe customize a Walkman to my liking?

It's incredibly rare to find any still on a cassette portable. Same with finding headphones, the vinyl case, or in particular, the lanyard. I think it's heretical to alter something so pristine. Hell, I kept the vinyl football sticker on the back of my WM-1. After 25+ years, I feel it has earned its place, hideous or not.