When deleting a trader, you have several options:
Simply delete — removes the trader immediately
Delete and blacklist — adds the trader to your blacklist so they cannot register again. You can specify a reason for the blacklist entry.
Delete and report to global database — adds the trader to a global SmartCJ database on the SmartCJ server. Any SmartCJ user can see flagged traders by hovering over them in their admin panel.
Delete to Trash — removes the trader from your active list and stops trading with them, but you can restore them anytime from Trade > Trash.