You should not worry about uploading after reading our ToS :
The models you send fall under our confidentiality TOS: http://www.mixamo.com/home/legal
Terms 2 and 3 cover all your rights to protected Data.
We judge the model based on it's animation ability. Being a company that has developed an auto-rigging tool we are testing it on submissions and having our animators test the quality of the deformation.