I dont think it is much of a concern usually in Vienna...
Though I have seen a funny little thing for when are you away a longer time... lits your lights up randomly as so if you were home...
You're right, usually Vienna is a safe place! Or at least I thought so. Never had ANYthing happen to me until last year. Now, just within the last half year, they've smashed my car window (just for fun obviously), stolen my bike, broke into my car and stole my wife's bag, robbed our place, robbed at least two other apartments in the house we live in... and a couple of weeks ago my wife's cousin got mugged, beaten up and robbed at the street, something which I never heard of in my circle of family and friends.
Well, I don't know if it's just a glitch in my personal statistics, but I'm starting to get a bit concerned!
By the way, Fabo, we had a radio and a lamp on timers, and our neighbors took care of the mail etc... Obviously didn't help! They robbed us before our plane even touched ground in Bangkok!
Fortunately no one told us, so we could still really enjoy our trip!
Gonna buy and install a new lock today...