Wow this swapping of lens thing is like those people putting balls underneath cups and let you choose the cup, Mr QuickHands indeed! Thanks for the heads-up. I'm glad I stick Dymo tape on all my stuff to differentiate. People who managed to steal and run away still can peel it off, but it will help deter people like Mr QuickHands and I can identify my stuff quickly.
I stick Gaffer tape...;p