calling custom validation methods in Rails

I just upgraded my rails to 2.3.4 and I noticed this with validations: Lets say I have a simple model Company which has a name. nothing to it. I want to run my own validation:

class Company < ActiveRecord::Base

  validate :something


  def something
    false
  end

end

saving the model actually works in this case. The same thing happens if i override validate() and return false. I noticed this in a more complex model where my validation was returning false, but the object was still saving...I tried it out in an essentially empty model and the same thing applied. Is there a new practice I am missing? This doesn't seem to be the case in some of my older rails code.