I was messing around with a Scenix (Ubicom) SX28 device. They were the last of the common micro's I have yet to really mess with (no desire to use them really).
Guess what! I was messing around trying to figure out which output of their configuration fuse array was the lockbit wire output and I noticed that the chip was sometimes saying, "unlocked' when I locked it with test code inside! I then came to realize that just the low halogen light coming through the objective focused in that area alone is enough to mess the output of the security fuse up! I read the device a bunch of times and in testing found that 3 of 5 reads under low halogen light in the area let me read the chip out without physically touching!
This is really scary! I can now say Atmel really is the most secure microcontroller on the market and has been for well over 2 years!
Congratulations Atmel! Learn from Ubicoms carelessness (Actually, I don't think Ubicom cares at all).
Fyi.. Many of you use various chips and not just AVR's so this is enlightening for some.