I found the ice vanes (separators) open (handles pulled) when I went out to fly the airplane last week and asked the last pilot if he had done it and why and he gave me that excuse even though the runway is asphalt and generally clean. I had never heard of such a thing, which is why I seek advice here, since there must be a lot of experienced PT6 operators reading this. I am not necessarily against it but told him to stop doing it until I could research the subject. Same as the windscreen heat. I have lots of hours on Boeings, HS748, Herald, etc but not all experience transfers. Only a little on King Air.