
I can. ?
The DRF system is radically different from the BRF system.
It's really very simple:
Mary (and our Marie for that matter and beforehand PH as well)
holds the exact same rank in regards to the protocol as the royal she is married to - always. I.e. the Crown Prince.
Except in some Constitutional matters.
The only ones in the entire country Mary does not outrank at any time, are QMII and Frederik. - And the Rigsforstander if Mary hasn't been appointed.
She even outranks the Prime Minister and the Chairman of the Parliament (who outranks the PM.)
Mary is always the Crown Princess and it doesn't matter if she is with Frederik, if she is alone or if she is together with QMII and Frederik is not present.
So when Mary is going solo, she is not princess Frederik, she is still the Crown Princess. And as such she outranks everybody else present. And also because being the highest ranking DRF member present, she is the direct representative for the Monarch.
Examples: When M&F are together, Frederik outranks Mary slightly, because he is the Heir. But if Joachim and Christian are also present Mary outranks them as well according to the protocol. Mary also outranks Benedikte.
Now, the DRF are not as formal in regards to interactions between family members. A kiss on the cheek usually suffice. Except when the show is on. Then Mary (and Marie) curtsy to QMII. But Benedikte does not. Because it would be seen as somewhat odd by the Danes if Benedikte should curtsy to her sister.
And AFAIK the DRF do not bow or curtsy in private. There a kiss on the cheek will do. They are after all family.
Another example: Mary is solo, no Frederik. But Joachim and Benedikte are present. Mary still outranks both of them. And if the protocol was strictly observed, Joachim should bow and Benedikte curtsy to Mary.
Also, in this situation Mary walks in front.
And when the time comes and Christian becomes crown prince, Mary will still outrank him - except when he is Regent. Because while Mary will always outrank her son, (until he becomes king, if Mary outlives Frederik) in regards to the protocol, it's another matter when it's in regards to the Constitution. You may recall when PH had his fit and ran off to France, because he was annoyed with being eclipsed by his son.
QMII was off duty, so Frederik stepped in in her stead at the New Year Court for the diplomatic corps. That's because
the Heir automatically steps in when the Monarch is away or incapacitated. That is crystal clear in the Constitution.
As such it was Frederik who received the well wishes from the doyen of the diplomatic corps, and in return wished the diplomats a happy New Year. Not PH. Because Frederik acted on behalf of the Monarch in a state affair - dealing with foreign diplomats.
And that takes me to back to Mary. Let us say that both QMII and Frederik are off duty at the next New Year court for the diplomatic corps and she is taking over. Then she will be both the host on behalf of the family, because she is the Crown Princess, but as as the highest ranking DRF member present she will also speak on behalf of QMII and Denmark. I.e. she acts in a Constitutional capacity.
She doesn't need to be appointed Rigsforstander to do that, especially as Christian will still not be crown prince.
When Mary acts as Rigsforstander, no one in the country outranks her. Not according to the protocol and not according to the Constitution. She is the acting head of state.
- Hmm, I may have made this rather simple explanation more complicated than it really is. Oh well.
ADDED: At present Marie outranks everybody else in the entire country, except QMII, M&F and Joachim. And that's because she holds the same rank as Joachim in regards to the protocol.
That also includes Benedikte, except when Benedikte acts as Rigsforstander.