i'm glad i live in the middle of a mile long road with only about 10 houses on it in a row! don't think our box has ever been vandalised (touch wood)!
if i did see one open i definitely would report it though.
would it not have made more sense for these things to be underground with grid-like lift up covers? i know it can't really happen now, there must be millions of them!
not sure if this has been mentioned, only read 7 pages of this, got to the animal pee bit
(engineers - carry a bottle of dettol spray maybe???), but isn't there a privacy issue - could someone listen to your phone calls through an open box??