copy protection

[Viktoras Didziulis]

Hi, 
what tricks do you usually use to tie an application to a CD to prevent it
from being copied ? Are there any "native" tricks that can be implemented in
Rev? No extremely strong protection is required, just to prevent ordinary
users copying and redistributing a live cd database app until about 200
copies of it are sold. Well I know the most simple way is to write "Please
do not make copies of this CD", but usually it is not very efficient ;-)
 
Best! 
Viktoras