Surely closing SOME airspace is reasonable, but I an not so sure about grounding the whole Europe....
Be it as it may, thing that pisses me more was the WAY it was done. I have my glider training on an airport that is right under the TMA of Pragues main airport. Usually, we coordinate our maximum altitude. This time, THE WHOLE TMA was marked TFR. CAVOK day, I could have done my stalls and spins, but no. We could not even do the regular stuff.... oh well.