Roger, what you say seems about right, but the effect of the fines campaign is to drive people away from renting out, which certainly wouldn't increase tax revenues - just a one off series of fines. How much more sensible to restart a programme of inspecting and licensing suitable properties, which would have to show they met defined criteria, and which would then provide a permanent tax revenue stream.
Jenny, I've been doing more interesting things My intent was only to calm down unfounded speculation over numbers, which seemed to have developed its own momentum. In the British Embassy post on the FCO website mentioned by palbar they say "The British Embassy has become aware of a number of cases where homeowners have been fined up to €30,000 for letting properties". That doesn't sound like thousands of cases to me. The full text is here: