I assume a missed opportunity to have the system checked and if dangerous problems are found brought up to code. On one hand that seems like a good way of forcing cheap landlords to have dangerous wiring brought up to code at their own expenses, but on the other hand any wiring older than let's say 25 years would probably be classified imminently dangerous, grossly reducing the opportunities to get an appartment unrenovated with cheap rent, update the wiring at your own expenses and enjoy the low rent. Especially students and young people in Vienna often have hardly any other chance of getting their own apartment unless their parents are willing to pay huge sums.
As an example: a 40 square meter apartment (small by Viennese standards) in new construction would be about 400 Euro/month at best, tendency going up with the quality. An old unrenovated (usually nicer) apartment could come less than 100 Euro if you were lucky.
OT: People with really old rent contracts pay 90 Euros for 200 square meter apartments smack downtown...
