Are you seeking concessions? Do you need a change in culture? Is your union making unrealistic demands? These are just a few factors to consider prior to developing a contingency plan. If you are seeking concession, the union will be reluctant to accept changes. You may face a very determined and aggressive group of activists. This in turn will require a more robust security model. If you have an entitlement culture that needs to be corrected you will have to alter how people they think. There will be those who are reluctant to change. These individuals will be aggressive while on strike. It takes a long time for entitlement to creep into a workforce and even longer to change it. If a strike results from changes being proposed, you will need to have a contingency plan that recognizes the potential for aggressive picketing.
Remember one size does not fit all situations. Take the time prior to develop your strike plan and understand the issues and how your union might react as this will dictate the level of response required.