I was installing Growl from the Mac AppStore and got this message.

I didn’t know they could detect applications installed outside of the AppStore. Can they do non-AppStore to App-Store upgrades (paid or not)? Anyone else get this message before?
 
	
I was installing Growl from the Mac AppStore and got this message.

I didn’t know they could detect applications installed outside of the AppStore. Can they do non-AppStore to App-Store upgrades (paid or not)? Anyone else get this message before?