I have never had a warning for getting close to the gold limit (I have tutorial tips set to critical only) but I agree with you. Also something should come up when you actually hit 100k, so that you don't waste anything.
I concur. It makes it sound like the limit is 70,000 or something. Nobody gets that much gold that quickly, unless they turn crowns into gold, and even then, they can't purchase more than 25,000 in a single transaction.
I'm also willing to bet that KI prevents you from buying more gold than you can hold, anyway.
When one considered that you rarely, if ever, get 5,000 gold or more from a mission, it would make more sense to warn at 85,000, once, at 90,000 once, and after 95,000 every time you get more gold.