Southlake
Mack 3 is not the only one. Fat Phil was wearing a team colored jersey yesterday. I believe that Bob Stoops does as well.
You know very little if you think a HC is going to sometimes signal a play in. Players are taught to only look at one person for play calls. That person is solely responsible for communicating the play in. Others on the sideline may as well, but are decoys or are signaling to other members of the team (line calls, etc).
The exception would be when the HC is actually calling the offense and/or defense. Other than Mike Leach, I can't think of a Div-1 HC who actually calls the individual plays. He may have input or override the OC, but is not calling every play. Since he doesn't call the play, it would be ridiculous for him to signal it in. Since he won't be normally signalling the play in, the QB will not look at him for the play call and any signal he would make would not be seen.
Admit you were wrong on the justification for Sherm wearing a non-team colored shirt. I appreciate people sticking up for him at this point, but that was a weak argument. Players will not be looking at him for play signals, period. With the new clock rules, there is no way a QB will look at anyone but the main signal giver to get a play call. If Sherm wants input, he can call the player over and talk to him, but he will not be giving signals from the sideline.
I don't know why Sherm decided to dress like a slob, but it was not to be more visible on the sideline.
Yet another point I just thought of. Every signal callers shirt you see will be a solid bright color so that the signals/motions will stand out. Why would a signal caller wear a shirt that makes it almost impossible to determine things like number of fingers or exact arm positions against, like a khaki or gray shirt does. Wouldn't maroon make a much better backdrop for those signals? Like what the coordinators and other coaches on the sideline who do signal wear?