acts_as_paranoid.rb

# Model

class Model < ActiveRecord::Base
  default_scope where(:hidden => false)

  def hide!
    update_attributes!(:hidden => true)
  end
end

# Controller

ModelController < ApplicationController
  def destroy
    Model.find(params[:id]).hide!
  end
end

# Examples

Model.all # won't return hidden records
Model.where(:hidden => true).all # all hidden records
Model.unscoped.all # hidden and unhidden records