MissedApproach From Canada, joined Oct 2004, 713 posts, RR: 2
Reply 2, posted (10 years 2 months 1 week 1 day 20 hours ago) and read 2190 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.