FWIW, in Spain we made our rules to say:
* The photos can be published using the [[Wiki Loves Monuments Upload Wizard]], designed to help in the participation on this contest.
* Those uploading their photos not using this wizard must indicate their participation manuall adding the code {{Wiki Loves Monuments 2016|xy}} to the image page.
Also, a similarly designed point is:
* It is the participant responsibility to ensure that the photos are tagged with a valid identifier… (ie. if they didn't put the right identifier but someone else did for them, that's ok, but they shall not rely on it)
Regards