Currently, I doubt it's crossed my player's minds, and if it did, the adventure is City of the Spider Queen, so usefullness is limited at best.
I'd love to see some cavalry action, though, and it was my first thought when I started scanning Red Hand of Doom. I look forward to running that adventure for the mounted combat possibilites alone. Such a classic/stock fantasy image needs to be supported better!
Just got PH2 today, I'm really looking forward to closely examining the Knight for that reason.