SpriteV1 Wrote: I don't believe so, considering every user who buys you plugin will have the same .jar file. Sorry.
Aaand that's where you're wrong. You don't get the same jar file for paid plugins if the file is in .jar format (not zipped or anything). The Spigot website injects your user ID into the jar. If too many servers are running it at once, the license will be revoked and you may potentially (usually always will) be banned. On top of this, many plugin developers implement their own DRM/anti-tamper that can also detect leaking.
In other words, remove the protection and if applicable, the developer's DRM scheme before sharing. Sharing in an uncracked form will do more harm than good and you'll just end up wasting money and your Spigot account banned.