"For us to break the fourth wall, either our creators would have to desire it or be pretty bad at running simulations."
There is also the possibility that, assuming we live in a simulation, the creators simply do not care or mind whether they are discovered or not. This would also leave open the possibility of breaking the fourth wall.
If it is... I hope they do not crash the system with the test.
http://www.huffingtonpost.co.uk/2012/12/12/physicists-universe-simulation-test-university-of-washington-matrix_n_2282745.html
Be sure to check out the actual reseach papers linked in the article! I would have linked to them directly, but the article is full of follow-on links of considerable interest.