From Horizons to date, more thousands of hours than I will admit to, I have been attacked by other Commanders a few times, three that I can distinctly recall (my memory sucks though). On two of those occasions the other Commanders claimed I was the aggressor, but all I did was run from them once I noticed they were shooting at me, so who knows what actually went down.
Dozens of times for sure, maybe hundreds, I’ve ran into random Commanders and joined up for a bit to get something done, with nobody even trying to murder anybody.