I am not a big believer in Unexpected IMC. In my 14 years of flying, I have never had an unintentional "VFR into IMC" experience, and I think this is because people tend to push on when they can see the weather is turning crap. Turn around early, go home, fly another day.....I think it all boils down to bad decision making, and maybe the PPL should focus more on decision making because the number of PPLs I have come across who have "flown into cloud" is amazing. Even a mate of mine, on his QXC ended up above cloud and had to spiral down through a very small hole.....hmmm......