Rails database defaults and model validation for boolean fields

I've solved this with:

validates_presence_of :is_subscriber, :if => 'is_subscriber.nil?'

From here

If you want to validate the presence of a boolean field (where the real values are true and false), you will want to use validates_inclusion_of :field_name, :in => [true, false] This is due to the way Object#blank? handles boolean values. false.blank? # => true

Or in Rails3 way

validates :field, :inclusion => {:in => [true, false]}