I am actually of the opposite view: if you have it, wear it! In fact, I think more people should wear tiaras at these types of events - be it royals or non-royals. In the case of "non-crowned" royals, wearing historical pieces like that is a excellent and elegant way to show a bond with the family's history. It is way better than having it gathering dust in some vault or just sitting in a glass box in some museum imho. Selling them off just because they are "ostentatious" to then be broken up never to been seen again is just sad. If it is due to other reasons (like splitting an inhertiance etc) it is of course more understandable.

And I must say that I much more prefer this tiara on the Crown Princess to the "difficult-to-spot" necklace she wore in her hair for Crown Prince Frederik's 50th birthday banquet.

But of course, this is just my opinion. Anyone is obviously entitled to their own .