After checking the logs as well as the screenshot, there's not enough evidence there to warrant a ban.
In fact, Sandersson's comment about him thinking you were an enemy does appear to match with what Daruvian said in chat at that point:
because you swung at me and killed my horse
Daruvian has no prior ban history
of teamkilling so there's really nothing to base something like this from.
On that note, I have seen you get a number of teamwound reports, Daruvian, so maybe watch your swings/horsebumps a little more closely.
As I can't tell if there were many teammates around you at that point, have to give the benefit of the doubt.
However, if another ban thread comes up like this with a nonchalant "whoops", that will count as a heavy warning, intentional or not.
