MacBook hard cover on the top half of MacBook ok?

You also risk changing bluetooth and WiFi performance by attaching some sort of hard case. It will also add weight. The lid might not stay open in the same way as the balance will be affected. Depending on how the hard case attaches, it might also add stress to the laptop structurally. Over a long time, this could distort the screen or worse. These laptops are exquisitely designed for all these things, why risk disrupting the function of the laptop for ... stickers?

Use your stickers to decorate something else.

No, for the same reasons. You can apply stickers directly to the case if you wish.

• My Macbook Pro looks brand new.
• It is 11 years old.
• It's seen a lot of travel.
• No stickers have even come near it.

I call that a "clue."

Anodized aluminum is tough but not sticker-friendly. Stickers can cause permanent stains that cannot be reduced repaired without replacing that section the case. On a Retina Macbook Pro. that measn the ENTIRE upper display assembly. Figure US$500-650 part and labor.

Do stickers on an Macbook Pro still sound like a fun thing?

"Decorating" a MacBook, and it's sleek design, with stickers is not the word I'd use.