I successfully removed the stupid "Warning: this airbag can kill you" warning stickers off of the visors. If you're curious about how the stickers work, read on:
The airbag stickers are made from thin plastic that's attached to the rectangular seam in the middle of the visor (two on the driver side, one on the passenger side). The seam surrounds the sticker and holds it on the visor. I don't think the seam can be removed without damaging the visors (it will leave a hole in the visor if you try).
Take a razor blade and carefully slide it into the sticker almost horizontally, being very careful to pierce the sticker without cutting into the visor. If you make a finger size hole in the sticker, you will be able to pull the sticker against the seam so that it breaks off cleanly all the way around the seam. Cutting around the seam with a razor blade produces much messier results. I ended up punching a small hole in the visor when I tried that.