JUST TWO BOBBY PINS??!!!!!! Oh wow...
You should use at least 2 to tuck the hair into the bun and then you should use a few more hair pins (they don't hold as long as bobby pins) to make it secure. Then she should have taken at least 2, one for each side to pull the hair over the side of the tiara and secure it on the side...
I'm guessing if it fell pretty soon, she used hair pins when she did the tuck..rookie mistake!!!!! I feel so bad, I could have fixed it for you
At least at her age, she didn't know the difference of good/bad FGITs but for $50+, I would expect the best of the best!!!