Know which way the wind blows
This is really very simple and all these referendums and political posturing are irrelevant. In time, the ruling elite will see if there are other countries that are not going to sign up for the treaty. If there are, the Czech Republic will provide the EU with a "yes and no" answer but will formally sign up after Klaus is gone. Otherwise, Klaus and Necas notwithstanding, the Czech Republic is not going to be the only EU country to stay out of the treaty.