现在有几个，过期前都没有出行计划，但是如果可以过期前订，过期后入住的话，应该
能用掉，谁能总结一下。
特比是下面三个：
Hilton: Free Weekend Night Certifciate
Marriott: 25k/35k/50k capped certificate (这几个应该都是遵循一个规则吧)
IHG: Free Anniversary Certificate
我查了一下，似乎IHG是可以先订，过期后再入住的，即便policy上明确说不行"and
stay must be completed(by expiration date)"。但实际情况是："It turns out
though that this stated term of the certificate’s validity is not actually
enforced. There are numerous reports of people being able to book a free
night during the certificates period of validity for a stay after the
certificate has expired"
Source:https://thepointsguy.com/guide/maximizing-ihg-rewards-card-for-free-
nights/
所以不能光看Term如何，实际情况可能不同。另外，Marriott的7-day certicicate可
以电话
