How do you invite the fugitives to such an event? If you know how to reach them you can probably arrest them no?
The article mentions:
..mail invitations to the last known addresses of approximately 3,000 wanted persons.
It is presumably much more efficient and effective use of resources to try and gather them in the same place, than individually surveilling 3,000 houses.
> For the marshals, arresting fugitives while away from home was significantly safer as they are often caught unarmed and off-guard.