Quoted from metallik:Problem is the new software combines with the existing playfield (which is copyrighted) to create a new derivative work.
IANA lawyer but...
Combining it with the playfield could *create* a derivative work, but as long as they are only providing things that are not, in and of themselves, infringing on a copyright, then they should be in the clear just as like with any product, mod, etc.
What purchasers of that equipment do with it (hook it up to their WW playfield, hang it on the wall, use it as a foot stool) is not anyone else's business.