There's a tone in using caps for sure, but it's probably best to leave this alone. Your supervisor has every right to emphasize something with you as your supervisor. It's one of those things that makes me grind my gears and pisses me off, but usually if I just walk away from it for a half hour, I'll feel better about it, take the feedback and try to just act on it.
IF she does this a lot and if it's hurting her team and productivity she'll probably get that as negative feedback from HER supervisor.
IF she does this a lot and if it's hurting her team and productivity she'll probably get that as negative feedback from HER supervisor.