Now that I'm actually thinking about this for the first time.
Is there any way there could be an automated filtering process that would omit human verified serial scammers, spammers and undesirables at each node?
A regularly updated 'shitlist' if you will. Not sure it will help with the disappearing activities but it may help prevent bloat on the blockchain...or however you choose to term it.
A simple no or non answer will suffice if this is just impossible. ;)
Just a thought...peace out...in
check out @steemcleaners, they're already doing it