SMA PLT FLEW WHEN US AIRSPACE WAS CLOSED TO VFR FLT.

Narrative

I MADE A LOCAL VFR FLT OF 30 MINS DURATION WITHIN 20 NM OF PETALUMA ARPT (O69) WHEN ALL AIRSPACE WAS CLOSED. I DID NOT REALIZE THAT ALL AIRSPACE WAS CLOSED TO VFR FLT. AT THE ARPT I SAW OTHER ACFT DEPART AND LAND IN VFR CONDITIONS. I DID NOT REALIZE THAT THEY WERE ON IFR FLT PLANS. THERE WERE NO SIGNS OR INDICATIONS THAT VFR FLT WAS NOT ALLOWED. I SHOULD HAVE CHKED NOTAMS; BUT FOR A LOCAL VFR FLT IN CLASS E AIRSPACE IN PERFECT WX; I OFTEN DO NOT. THE SHORT 30 MIN FLT WAS UNEVENTFUL. I LANDED; GASSED UP AND NO ONE SAID A WORD. IN FACT; I DID NOT REALIZE THE AIRSPACE WAS CLOSED TO VFR FLT UNTIL 3 DAYS LATER. OTHER PLTS I KNOW WERE GOING TO DO THE SAME THING; BUT WERE TOLD BY SOMEONE AT THE LAST MIN. PETALUMA IS AN UNCONTROLLED ARPT. INTENTIONS AND POSITIONS WERE REPORTED ON UNICOM; BUT NO ONE SAID ANYTHING. A SOLUTION MIGHT HAVE BEEN TO HAVE A SIGN POSTED AT THE FBO OR GATE LEADING TO THE HANGARS IN ADDITION TO NOTAMS. I HAD BEEN WATCHING THE NEWS ON TV AND READING ALL THE NEWSPAPERS; BUT STILL SAW NO MENTION THAT THE SKY WAS CLOSED TO VFR. FOR A CROSS COUNTRY FLT I ALWAYS CHK NOTAMS; BUT NOT NECESSARILY FOR EVERY LOCAL FLT IN CLASS E. I'M SORRY IT HAPPENED; BUT I REALLY HAD NO IDEA THAT THE AIRSPACE WAS CLOSED TO VFR. I HEARD THAT THE FAA CALLED THE ARPT AND REQUESTED MY N NUMBER. SO FAR I HAVE NOT HAD ANY CORRESPONDENCE WITH THE FAA.