Trying to understand a little ... so their wonderful jury system designates juries based on who happens to be online at the time of the Alert?
DU's manglement can't see how easily that could be gamed? Or won't? 
Right -
The loophole is there because there seems to be no time limit on alerting - As long as an undesirable thread hasn't been alerted on - DU members can wait until they believe the odds are in their favor by logging in at a quiet time (usually the wee hours of the morning) and finding posts by their target to alert on.
If the first alert fails, then another member of the alert group will take a stab at another post by the same user, etc etc. until they achieve victory.
This is
**BY FAR** the most effective technique they use to generate desired jury results. AFAIK, this technique was designed by The KKKlams, and they use it almost exclusively. Fixing the loophole is easy - set a jury-reviewable timeout limit to a couple of hours after a post is made.
--But that isn't going to happen. Skins would find himself flayed by the KKKlams if he took their secret tool away from them. Then we would have to refer to him as Skinless, and that just doesn't have the same 'ring to it'.