You are supposed to be more vigilant in areas where you get that warning. There is no reporting requirement; just keep an eye peeled for aircraft. There are several near me that see little or no traffic but it is nice to be reminded. Know that if a pilot using those dirt strips/backyard airfields sees your drone from his a/c he will more than likely report it. When I do get traffic if they see me they see me descending until the coast is clear. Any attention I get from the Feds I can show that I was not breaking rules at the time and took prudent spacing action when the plane showed up. If my flights were regularly nearing the actual strip I would make it a point to chat up the owner/operator to let him/her know I'm in the area from time to time and that when I see his plane I will descend until he clears the flight space.