下述句子（见补充说明）中的should是什么用法?难道should也可以表“可能”之意吗?

1.此句中的should表示条件,翻译为“万一”.
2.句中采用了if引导的条件状语从句的虚拟语气的倒装语法.
即：should you be unfortunate enough to have them stolen
= if you should be unfortunate enough to have them stolen
3.相关语法规定如下：
1）if引导的条件状语从句,如果使用虚拟语气对将来的倒装进行虚拟时,则if从句可以使用“should + 动词原形”或“were to do sth”或“动词过去式”来做谓语,主句则使用“would/could/might + 动词原形”做谓语结构.
如：If it should rain tomorrow,I would stay at home.
= If it were to rain tomorrow,I would stay at home.
= If it rained tomorrow,I would stay at home.
2) 而且,如果if引导的使用了虚拟语气的条件状语从句,且其含有should/had/were时,则可以把这三个词中任意一个提前至从句句首,并省略if.
如：If it should rain tomorrow,I would stay at home.
= If it were to rain tomorrow,I would stay at home.
= Should it rain tomorrow,I would stay at home.
= Were it to rain tomorrow,I would stay at home.