WW - I'm pretty certain they are using your kap_uav.lua script. I've been in email contact with them and suggested it.
Thanks Dave. If so, I'm wondering what version they are running? The latest ones use set_lcd_display() and that should work for all cameras unless there is a bug in the port.
Note that there is a short delay before the display shuts off to let you confirm that the script is running.
edit : I was pretty sure that this has come up before. Here's the link :
http://chdk.setepontos.com/index.php?topic=10822.msg122617#msg122617and there is a test script mentioned in the second post at that link. Might be interesting to have them try that. If necessary, we might need to tweak the sleep() commands around set_lcd_display() a bit.