Actually RPB did not tell anyone not to sing. That initative was taken by NEE and many RPB followed suit because we agreed.
For all the complaints on this board about "protest", I only recall 2 actual protests by supporters. The 1st was the demonstration at Gate 4 by about 100 fans and the 2nd was the green/silent protest of 2010, and yes I participated in both of them (for those who keep asking me "what do you do".)
There has never really been anything since. Despite our shockingly poor record. Which always makes me chuckle when I hear complaints about "all these protests". 2 protests in 6 years with a club that has this kind of track record is extremely forgiving.