I'm positive the radio story it's legit, I was on the ship and I've heard the recording of the woman who told about this argument, she wasn't kinda gossiping and she didn't sound like a shipper either, in fact it seems to me she found the altercation kinda funny, LOL! (Part I )
The recording was briefly storaged on the radio site (my former shippers group alerted me about it, haha! ) I remember pretty well the woman laughing and saying Cait’s badass and was likely uninvited or she wasn’t supposed to attend but showed up by surprise. Also some autograph/pic hunters were there while they left the event together and they said Cait looked annoyed.
haha DAMN wow. then I guess it wasn’t the Globes party since Cait was invited to that one. I was just entering the fandom around that time so I didn’t get to hear the recording or find out any details until later. thanks anon!