I'd be cautious about putting stickers all over your bottle. There are restrictions as to how many stickers you can put on equipment so a cover is the best way forward.Hey buddy, I'd just get a tank cover........for two reasons. A. To protect your tank, and B. As Matt says, just to stop a ref from running in thinking you've been hit. By all means slap more stickers on - no problemo at all if that's what you prefer!
The "rules" are there to help players more than to hinder them. It might seem annoying on the day when a ref calls you up on a vital bit of equipment, but it's more to help them to help you situation