Jamma's change of scrum cap at half time originated in the game where Hamish Smales took hate at him and appeared to make it personal after Jamma was told in no uncertain terms by Smales, to stop counting down after he had called 'use it'*. Scrum cap changed to bright blue at half time and I don't think Smales penalised Jamma again in the game. Now I think the scrum cap gets changed every half time
* I've long advocated that our fans should initiate a countdown. I remember one SH took over 11 seconds to 'use it' and the ref (Doyle) just let him. Wayne Barnes himself started counting down once when Dobby was taking his time. He got it away damn quickly when it happened.