I see jail and tidal waves in your future

Romania is considering punishing witches and fortune tellers if their prognostications do not come true.

Why bother fortune tellers, you might ask.  For one thing, the proposed law is aimed at  Roma, or the people who used to be called "gypsies." 

Romania must have more pressing problems than cracking down on something so trivial, but apparently Romanians are superstitious. Extremely superstitious.

But the parliament apparently did not figure out that the anti-fortune telling law is a logical riddle.

Suppose a man goes to a fortune teller, who predicts he will get hit by a falling piano. The man, who lives near a piano factory, goes home by a circuitous route to avoid the factory and any falling pianos.  In this case, the man relied on the fortune teller, and took evasive action. 

If a piano did actually fall, he would have escaped harm thanks to the fortune teller -- but then the fortune would be incorrect and she would face criminal charges.  Seems like a paradox.

Or suppose she predicts vaguely  that a client's relative is going to experience health problems. The client  could then take the relative to the doctor for a check-up and thus double-cross fate. The logical fallacy actually works in favor of the people he or she cons.

Unless the fortune teller specifies a certain date, she can always claim that the event is in the client's future. Eventually, decades down the road, the  client will develop a disease and will die.  "Health problems" inevitably happen at some point in a person's life.

It might take decades or centuries for a piano to fall on someone's head.  Would the fortune teller be released from prison if, 20 years later, a piano happens to fall on someone?  Or would that just confirm that she is a witch?

Witches have their own angle. They can defend themselves by blaming the fortune-telling cards. This puts the card manufacturer in a fix. The card maker could then blame the company that made the stock on which the cards were printed, who could then blame the rags that the recycler delivered to make the stock.  This road extends to infinity, or at least, to the beginning of the universe. 

This is sort of a "you can't prove a negative" argument. 

Now ponder Earth's changing climate. Skeptical politicians who refuse to recognize the problem are in the place of the Romanian parliament, and the fortune tellers are scientists.

As the Romanian example shows, the scientists cannot lose. And this is assuming that climate experts are simply guessing. Either the climate does change (it's in the process right now) or it may change in the future.

Maybe the Romanian parliament is just the body to deliver global climate change laws.