Flight Crew Instrument; Flight Crew Private
Flight Crew Last 90 Days 40; Flight Crew Total 165; Flight Crew Type 160
Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Security
General Police / Security Involved
Airport; Procedure
We filed from ZZZ to RDD because of inclement weather and low ceilings. Because we were planning on stopping to eat at a restaurant in the terminal we requested parking; but were told to park at the GA ramp and walk to the terminal. Once we arrived we found the there was no way in and nobody was around so we called for guidance. The person was very helpful and after exhausting our combined ideas the person relayed to security that we needed help and to let us into the building. However; our reception by security was that of a security threat and we were immediately questioned about our intentions. We were also asked if we had seen the signs indicating that it was a restricted area. The signs would have been effective if they were lit but because it was night time and overcast we did not see them until the guard pointed them out. Our licenses and aircraft were photographed and we were told that what we did was equivalent to 'running across the runway at San Francisco airport.' Ultimately; we made it clear that we would not have entered such an area if we had known. Since this has happened; I've learned about other pilots that have accidentally gone into such an area and am realizing that what happened with us is a recurring issue. I believe that improving the lighting for the signs at RDD would help remedy this. Additionally; it may be helpful to identify restricted areas on the airfield diagrams.
Pilot reported inadvertently walking into a restricted area while attempting to cross the ramp at RDD airport. Pilot also reported that signage was not lit and therefore not visible prior to entering the area.