Yeah..i dont think the bride and groom should have to reschedule their wedding simply because Mary and Frederik cant make it. Why should one couple be given special treatment when you consider the hundreds of other royals that attend these weddings. I think in the end it all comes down to the fact that if Frederik and Mary had wanted to attend the wedding, they would have. They could've taken a few days off their honeymoon like Felipe and Letizia. The guests should be accomodating for the sake of the bride and groom and NOT the other way round!
I wasn't expectiong Frederik and Mary to be at the Jordanian wedding since no one from the jordanian royal family, or any other middle easterm royal family as far as I can tell, was in Denmark to attend their wedding.
As far as Felipe and Letizia's wedding is concerned, I think Frederik and Mary didnt show up because they didn't want to interrupt their honeymoon, and thats a decision they're entitled to make. But that still makes Felipe and Letizia the more considerate couple to me.