Where is the line drawn when it comes to allowed exploits?

[Dreadark]

TBH i believe that the innocents should be able to do whatever they need to do to survive (so long as it isnt gamebreaking) and if the traitors cannot get to the innocents, thats a win for the innos. That being said, zombies should maybe have some sort of climbing ability because I have seen this scenario many times on different maps and it just causes frustration in the spectators.