At this point I think its more like the people trying to enforce the "happy birthday" song they bought the "rights" to. These pins are not being reproduced, and the guys that own the rights bought the WMS name from IPB I believe. So they have no stake in anything other than trying to make money off of a defunct technology that they are NOT trying to reproduce. Hell, I dont even believe they are supporting anyone that owns one! At least NAMCO brings out "PacMAN" style games so they have a right to enforce their IP.
Personally I think its just a power trip.
I was at Illinois Pinball in 2008 after the "buyout" and saw unfinished Pin2000 cabs and playfields still NIB as well as a BBB and a whole slew of the original artwork files. It would be great if the current owners of the WMS name would actually do something with this other than just look for IP violations.
But as this topic has been rolled over multiple times - end of my rant.