Actually webjunkie appears to be correct. From the paper:
> Average time before monitors connect. 40% of the monitors that communicated with our clients made their initial connection within 3 hours of the client joining the swarm; the slowest monitor took 33 hours to make its first connection.
The average time decreases for torrents appearing higher in the Top 100, implying that enforcement agencies allocate resources according to the popularity of the content they monitor.
And I doubt that if I download some rare indie music stuff, that anyone would care to monitor this torrent.