Yes I can only speak from my experience. I don't know if charging for my time or attorney fees to research and reply to their claims would have panned out. However I can tell you that had they continued to hound me I would have tracked my time, met with a legal representative, and submitted an invoice. I'm not sure where it would have gone from there.
If Getty decided to actually file against me I know I would have fought them in court. I would have made sure my lawyer friend racked up a LOT of billable hours in support of me and I'd have filed a counter claim. But I'm glad it didn't go this way because, although although I'm fairly certain I would be vindicated and it would cost them, it would have been a huge time suck for me.
By the way, I think they got a sense from me that I was absolutely willing to go to the mat on this. I think they made a decision that if they dropped the whole thing, I would too. Unfortunately (for them) I found their business model to be so abhorrent I have made it my personal mission to get them to change it.