From my understanding, it is the commercial
exploitation of the software, 
 rather than the sale of music written with the
software that they are
 trying to limit: so if you were to build a linux based synth, and sell it
 with LS installed, they would like to get some money from you for it,
 which they would not be able to do under the GPL.
 James 
 
It seems that one company already has used it. I wonder why it should
be OK for them to use it and not others? ;-)
- Mark