Not because it's a feudal society. The king's too powerful, has centralized too much away from them, and the first thing he would have go is their authority to raise private armies. Even retainers are dangerous, and a noble would be at least fined for retaining them.
On the other hand, memories are long. Loyalty is strong. . .
Perhaps I can put the rebeliious nobles up in the borderlands, where, as all the courtiers know, folks are old-fashioned. With such quaint virtues as personal loyalty to their lords.
Perhaps I can have the king rage and fine a noble severely for the number of retainers he has, thus foreshadowing them some of them have forces. (Queen Elizabeth I once questioned her grand reception at a noble's hall and deduced it was time to fine him for having too many men.)
Or, of course, both. . . . wrestle, wrestle, wrestle.