The suggestion that Queen Mathilde chose a "modest" tiara so that she would avoid an embarassment for the tiara-less Empress Michiko sounds quite far-fetched to me...
Two years ago, Empress Michiko already welcomed the Dutch King and Queen without a tiara on her head, and at the time nobody suggested that Queen Maxima's whopper Wurttemberg pearl tiara was too ostentatious towards the Japanese Empress...
Nice to see a tiara anyway on Mathilde (though this Wolfers tiara is definitely not my favorite)!