Maybe in our real life we might have ssen such a scene.might have done 是虚拟语气,或许在现实生活中我们原本可以看到此景.（实际上没看到）
Maybe in our real life we haven't seen such a scene.不是虚拟语气.只是在表达一种不确定,或者是在感叹眼前所看到的景色.