Lucky Luke on CD-i: "Don't shoot the pianist" message left blanc in the game itself, but still there in the booklet

The instruction booklet of Lucky Luke CD-i shows some pictures of the game itself but there are a few nice differences. CD-i member Jongg-eater, Jorne and Retrostuff observed the text above Lucky Luke while playing the piano, which sais in Dutch: "Don't shoot the pianist". This is inspired from the original Lucky Luke cartoons, where there is a similar sign above him, like you see below:

This scene was obviously taken from here, but it is used in many Lucky Luke adventures. What's interesting: this sign is not visible in the game itself, the paper is blanc, like you see below. Perhaps as the sign was written in Dutch?