FYI, All:
You no longer have to ask a curator for when a user was last on-line.
Simply go to the profile of the person, click the Actions button, select Report item.
If that person has already been reported, there will be a message to that effect.
Otherwise, look at the "Reason" list:
If the person has been on-line recently, there will be NOT be a choice of "Abandoned Tree".
If you do have that choice, then you can report the person as having 'abandoned' their tree yourself.
There is no guarantee of any action (Geni's staff has many criteria to consider before possibly taking any action), but you should get an email notification (if you haven't turned them off!!) when they begin to consider your request. You will NOT get a followup note as to what actions they may have taken (for privacy reasons).