create default timezone, disable user-set time zones

I run a regional site ( http://www.democracyformo.com ), everyone on the site is either in CST or would understand that it is CST site. There is no reason a user should be able to set their timezone for this site. Users timezones default to UTC. It creates problems, especially with the event module. I believe there should be an option to remove it from user preferences and set the timezone for the entire site.