No base visit yet, which is nice.
I have seen some UFO's doing what appears to be a search of my base, but so far they haven't found it or attacked it. I say they were doing a search, but as I don't have a HyperWave Decoder, they could have just been out for a slow sunday afternoon drive.
I don't know if it makes much difference but I don't actively attack UFO's and shoot them down, infact in my LP I haven't shot down a single UFO. I let them land naturally and take them from there. Perhaps my tactics are reducing the chance of retaliation.