Double adultery had some impact on it as the child of a married woman is legally the child of her husband. It would have taken a court case proving that the baby was not the child of Sybille's husband to get his name of the birth certificate. That would have been a major scandal including a social stigma even if her father had been an ordinary man, let alone the first in line of succession.

By getting the style of HRH and title of princess of Belgium for herself and her two children there are now 3 more people who could cause scandals by using those titles so that means the monarch and the government will have to go in damage control mode. If the King of Sweden can strip his own beloved grandchildren of their HRH im fairly certain Philippe will have little trouble doing so with his halfsister and her children. Remember he has had to deal with one sibling who does not always understand how to act in his position and Delphine so far has displayed the kind of behaviour that will lead to more issues and neither Philippe nor Mathilde will stand for that. When the law that now gives Delipine and her kids the style and titles was introduced it was for the offspring of Albert, prince of Liege. A few years ago it was limited to children and grandchildren of the main line. I expect that will be followed up by limiting it even further. That might also impact the children of the kings full siblings but it would be in line with what we see happening in other monarchies. Shrinking the royal family or the royal house to a handful of people in the main line and leaving junior lines to fend for themselves in normal jobs. With the added bonus of being well connected and often well educated.