Video from 2014 shows an al Qaeda in Yemen or al Qaeda in the Arab Peninsula (AQAP) raid on a Shia Houthi encampment. The Houthi base was being observed by Sunni militants to develop their strategy. The AQAP fighters rolled up in a single pickup, hiding behind half drums to conceal their intent. The Houthis were caught off guard, and the entire camp was taken by the AQ militants.
Do you think this raid would have been successful against a Western military encampment? What would AQ have done differently if attacking a conventional force? Initiate with a SVBIED? This is a prime example of why you have LP/OPs set up outside your perimeter to give you advanced notice of incoming vehicles. This also demonstrates why you need to have at least one maneuver element out patrolling the high ground above your post to interdict this kind of observation and intel gathering.