Most people don't need instructions about what they're supposed to do in a restroom. We were all potty trained as infants. We can handle our own affairs in that department.
If we did need instructions, though, we don't think this sign would help. We've read it multiple times. We still have no idea what it means. What goes back toward our behinds? Do we go into the bathroom backward? Is this a wiping instruction? We're lost! Maybe we'll just wait until we're on the plane.