They were bold? Bollocks!!!
I could have accepted a slight reduction in the number of movements, but a complete standstill? If the controllers are swept off their feet, being rendered completely unable to handle even two aircraft per hour, because of a little bad news (no-one will be fired, and the possible relocation isn't until four years from now) ; then they should be looking for a new line of work.
If you want to go on strike then do so; do it by the book and call it what is.