Question About Getting Gold - Did I do something bad?

So I have a question about getting gold in Boss fates specifically. I did some reading up on it and it seems like it's pretty difficult to determine what exactly decides who gets gold. I do know that being in a group helps though.

I was playing yesterday and I ended up leading the assault on Cancer outside of Costa Del Sol. I'm pretty sure I got the first hit off since he pretty much laid me flat in about 2 hits after that initial hit. I respawned and came back and continued the fight. At the end of the fight I ended up getting the gold for the fight - which from what I've been reading is pretty darn difficult to do solo. But I'm confused about one thing and that's where my question comes in.

Since I was solo and I got the gold, does this mean that I cheated everyone else out of getting gold? Or would it have also been distributed to anyone else who had either been healing or tanking? I just want to make sure I'm not inadvertently cheating people by soloing bosses like this.

As far as I understand it there's nothing about the FATE reward system that prevents every participant from getting gold. The requirements are a bit sketchy, but outside of there just being too many people for the boss to survive long enough everyone should be able to get a gold rating. Being in a group is only 'required' for gold when the FATES are swarmed with a ton of people (mostly just Behemoth and Odin at this point).

Ooh okay, that's good then!

I remember when I joined in on the Behemoth fight (somehow managed to survive meteor) I had noticed that a bunch of people got the achievement at the end of the fight. I didn't see that last night when we took out Cancer. But then again I could have just been fighting it with people who were just leveling up a new class and have already done that particular FATE before.

Hypothesis (completely unproven): The top X people on agro participating in the FATE receive gold rating. Being in a group somehow let's you take credit for your group's agro.

So if 1 person solo's 99% of the FATE and 5 people show up just at the end and tag it with smallest ability, then all 6 should get gold assuming X is at least 6.

Anecdotal evidence: I've showed up late and done almost nothing to get gold. And in a high participation FATE warrior just run up, hit 2x Butcher's Block (high agro, low damage) then leave and still get gold.