A writing slip up?

One of the odd things that was weird to me was that Julia said the meadow was safe that implied she had done the hanky panky with over men before, yet none of the men beforehand have seemed to have never been caught by the thought police other wise she would have been arested sooner via being ratted out. Now I think it is very unlikely that the men before have never be caught so is it more likely that Big Brother was actoully using Julia to lure men unknowingly, if so why did they stop at the end of the book?