通过 false 终止回调执行不起作用，google 一番未果，怒跟源码，发现如下：

activesupport-5.0.0.1/lib/active_support/callbacks.rb

def deprecated_false_terminator # :nodoc:
  Proc.new do |target, result_lambda|
    terminate = true
    catch(:abort) do
      result = result_lambda.call if result_lambda.is_a?(Proc)
      if Callbacks.halt_and_display_warning_on_return_false && result == false
        display_deprecation_warning_for_false_terminator
      else
        terminate = false
      end
    end
    terminate
  end
end

需要用 throw(:abort) 终止回调执行，官方文档还未更新

http://guides.rubyonrails.org/active_record_callbacks.html#halting-execution

国外一哥们的总结：

http://blog.bigbinary.com/2016/02/13/rails-5-does-not-halt-callback-chain-when-false-is-returned.html