Ah, I missed that part. Had to go to Flickr to see it. I would certainly choose a less destructive method to attach the mouse and coiled cords.
Since you more or less gavethis paint-joba thumbs up, I was surprised you had any issues with the painting. Though I think we agree any painting should be done sparingly and only if the case is in poor condition, beyond restoration, which may or may not have been the case with respect to the CC you weighed in on. That said, I think taste plays a big part in determining what is acceptable. I would be quite happy to have an orange compact just like many people opted for the tangerine iBook and orange iMac. While, on the other hand I liked the CC mod, but not the final paint-job and stickers. This makes painting it a particular color neither right or wrong.
We are in agreement that permanent changes to the case are not acceptable. Gluing anything to the case or cutting holes in it should not be tolerated unless the case is already in disrepair and is being converted for a specific productive reason. The CC mod mentioned above is well done and serves a purpose to extend the life of this classic Mac in the spirit of the original. Gluing a mouse onto the top of a Mac serves no preservational purpose and could indeed be accomplished by other less destructive means. I put these types of approaches to any Mac into the same category as those who would stuff a CD-ROM into a compact without giving any thought to the finished aesthetic or history of Apple's design.
The only exception to this rule is if the hardware is completely dead and the case is also damaged and in poor shape. Let's face it, this 20+ year old hardware is failing to the point it cannot be easily repaired and all of it will eventually reach a point where it cannot be satisfactorily repaired. Eventually all there will be are cases and most of those yellowed. In this case, I would still limit my mods only to those in poor condition. So make speakers out of them, or MacQuariums, or whatever. Frankly, the Mac-O-Lantern could easily have been made out of a damaged case and just for the holiday, slide some working hardware into it.
In the end, I guess it is far better someone finds a use for them at all, no matter what modifications they perform, rather than dumping them into a landfill, regardless of what the members of this forum would prefer.