I would use [Selenium Builder][1] instead of Selenium IDE.   If your script was exported as Java, then you just do this: 

    WebElement checkbox = driver.findElement( By,id('the_id' ) );
    if ( checkbox.isSelected() ) {
      System.out.println("Checkbox was already selected: " + checkbox.toString() );
    } else {
       checkbox.click();
    }

I use [this project template][2] to run my Builder scripts.


  [1]: http://sebuilder.github.io/se-builder/
  [2]: http://djangofan.github.io/maven-selenium-builder/