Re: What is "system events" ?
You’re twisting the concept. Anyone on an AppleScript mailing list should expect to get posts about AppleScript. Being on more than one list of the same subject and getting duplicates of the same message isn’t “crossposting”.
Crossposting means sending the same message to several diverse groups. Hence “cross”…both in terms of crossing subject-specific content and in terms of audience reaction…
If you object to getting messages about AppleScript in an AppleScript list you’re subscribed to, either complain that the message is off-topic or, if you get no joy, unsubscribe from a list that doesn’t cover your interests.