personally I feel if you have gone well out of your way to find original modeler for some meshes (that contained no claim of ownership or even read me files) especially things you downloaded from freebie sites and have modified putting them up with a notice of what has been done to them and that you will take them down all the orignator needs to do is contact you and you only host them on your site relieves you of much responsibility, but not all. I mean I am thinking of putting up half a terabyte of models that I have collected over the years that have no claim of ownership, partially to find the owners and get updates. The were free to start with, with no restriction on use, I considder them abandoned claims that should be shared with the world like any other archealogical treasure.