MissedApproach From Canada, joined Oct 2004, 713 posts, RR: 2
Reply 2, posted (9 years 1 month 3 weeks 5 days 17 hours ago) and read 1640 times:
Could be just a regular patrol. They step things up depending on the perceived threat level. This is most likely related to the attacks in London.
Right after September 11 they operated patrols on a schedule, until someone pointed out that predictability is the enemy of security.