At any rate, if the guy was in fact a contractor, then he probably had a contractor's badge granting access through the main gate and walked on in.
I have been checked by civilian and/or military security to get on the bases in the San Diego area... just recently security stopped requiring a base sticker on your cars, all u had to show was an ID card and u are good to go...I cannot remember the last time any one checked my car trunk or etc...so it very easy to get on a base IMO