We had a similar case on this not long ago and it was pretty much concluded that pushing a player near/off a ledge is KOSable no matter what, as the rules pretty much state that in the valid KOS reasons and T-Baiting section (as Nina has posted below).

Also, as Kyber mentioned, if you saw that this player had not done anything to warrant being pushed off the ledge, then you had even more reason to KOS McSlaughter for doing so.

We had a similar case on this not long ago and it was pretty much concluded that pushing a player near/off a ledge is KOSable no matter what, as the rules pretty much state that in the valid KOS reasons and T-Baiting section (as Nina has posted below). Also, as Kyber mentioned, if you saw that this player had not done anything to warrant being pushed off the ledge, then you had even more reason to KOS McSlaughter for doing so.