And how would they spot someone picking up your suitcase even if they had cameras? So many suitcases look the same these days, unless yours was particularly unusual, I don't see how they could identify it.
Even if they could, how would they identify the person that picked it up? Wouldn't you have seen it on the luggage belt and stopped someone from nicking it?
What difference does it make now anyway - it's missing. Whether it be in Spain, in Timbuktu or been stolen, you don't have it so it is irrelevant really what has happened to it.