Policies that restrict outsiders are common. Some justifications include protecting insiders from high price and leaving more of the concerned products to insiders. Sometimes these policies fail to work because outsiders can get around the restrictions. In a model in which a policy of restricting outsiders is anticipated, we find that if the policy works, it only sometimes lowers the price. When the price does decrease, the product quality decreases too. Not every insider would benefit equally; those insiders who likely suffer are identified. While restricting outsiders may or may not reduce insiders’ consumer surplus, outsiders and the producer are always worse off. They therefore would find ways to get around the restrictions. Evaluating these policies must (a) take into account the possibility that they might not work at all, (b) check their effects beyond just price if they do work.

限制局外人的政策很普遍。一些理由包括保护内部人免受高价侵害，并将更多相关产品留给内部人使用。有时这些政策无法奏效，因为局外人可以绕开这些限制。在期望限制外部人的政策的模型中，我们发现，如果该政策有效，那么它有时只会降低价格。当价格下降时，产品质量也会下降。并非每个内部人士都会平等受益。确定那些可能遭受痛苦的内部人。限制局外人可能会或可能不会减少局内人的消费者剩余，但局外人和生产者总是处境更糟。因此，他们将找到解决限制的方法。评估这些政策必须（a）考虑到它们可能根本不起作用的可能性，