Is it no okay to use Mock-up?

Before when i was new here in DesignContest then i use mock-up for my design someone reported me not to used mockup and it is actually on the terms and condition in other words rules here. i use tshirt some sort of a website face etc. but now many are using it. is it okay now to use such? pls give me clarifications.. thanks!

Yes the background rule was changed and updated a little over a month ago. Mockups are now allowed

oh okay sharie..but i think it is not good for the site because we will lose some sort of contest like t-shirt designing because designers are giving an idea to the CH a good designs. well any way thanks for the reply..