"A certain high seriousness"

Something of an aside, but I was amused to read this in the chapter by Chris Page referred to in yesterday's post. Referring to the Medieval Ensemble of London (active in the late 70s and early 80s) he notes approvingly (page 25):

"Their sense that the performance of medieval music in Britain lacked a certain high seriousness was reflected in their choice of tails for concert dress so that the four members might give the appearance of a conservative chamber ensemble." 

Good food for further discussion. 20th century formal men's wear and a conservative chamber concert atmosphere might indeed contribute to "high seriousness", but surely not to authenticity?