I think as long as your clients can understand the intent behind the design of the application and the intended usage of it, faking the data should be fine.
To me a mock-up is something like a photo of how the application is supposed to look rather than a tangible application. A proof-of-concept is a written application that is boilerplate for the most part that will allow the users to experience how it's used.
For further actions, you may consider blocking this person and/or reporting abuse
We're a place where coders share, stay up-to-date and grow their careers.
I think as long as your clients can understand the intent behind the design of the application and the intended usage of it, faking the data should be fine.
To me a mock-up is something like a photo of how the application is supposed to look rather than a tangible application. A proof-of-concept is a written application that is boilerplate for the most part that will allow the users to experience how it's used.