The problem is that we know all major jewels of the late Princess Charlotte de Monaco (the mother of Prince Rainier) went to her eldest granddaughter Princess Caroline. Often explained as a move to bypass Princess Gracia (who lived on non-speaking terms with her mother-in-law).
That is all. We have seen Princess Charlène borrowing jewels from her sister-in-law for her wedding, we have seen her with a Repossi collier. Is it owned by the Princess? Or was it a loan? I think it is difficult to condemn Princess Charlène without knowing how the situation really is at the Monegasque jewelry department...