So the bishops can't see yellow. Yellow is the symbol of rebellion and the call to it. The organizing banner as they gather their allies and come together, protected from the eyes of the bishops.
Red is the symbol of open and active rebellion. When they're making their moves against the bishops. Wearing the bishops own red colors to spite them in a flagrant and open showing of rebellion against their system and turning their own powers and tools against them.
But it's also the most dangerous. Because now they can see you. The protection of the yellow is gone and you are in their sights.
Clancy wears red.
Torchbearer wears yellow.
COVER ME (I'm wearing my rebel red and am in danger)
COVERING YOU (I'm wearing the yellow and will shield you as best I can)
