Overly zealous adherents to the "formal" understanding are referred to as Pedants, as illustrated below in a rather humourous article by Douglas Adams (brilliant author of the 5-part trilogy The Hitch Hikers Guide To The Galaxy as well as various other notable contributions to modern culture, may he rest in peace).
(source: http://www.douglasadams.com/dna/pedants.html )
Significant Events of the Millennium
1 January 1000 Almost everyone celebrates the beginning of the second Millennium. 1 January 1001 Pedants celebrate the beginning of the second Millennium.
1 January 1100 Almost everyone celebrates the beginning of the twelfth century. 1 January 1101 Pedants celebrate the beginning of the twelfth century.
1 January 1200 Almost everyone celebrates the beginning of the thirteenth century. 1 January 1201 Pedants celebrate the beginning of the thirteenth century.
1 January 1300 Almost everyone celebrates the beginning of the fourteenth century. 1 January 1301 Pedants celebrate the beginning of the fourteenth century.
10 June 1381 The Pedants' Revolt reaches London. (Not the Pedants' Revolt, the Peasants' Revolt. (sgd.) A Pedant. And kindly close the brackets.) (Thank you.)
1 January 1400 Almost everyone celebrates the beginning of the fifteenth century. 1 January 1401 Pedants celebrate the beginning of the fifteenth century.
1 January 1500 Almost everyone celebrates the beginning of the sixteenth century. 1 January 1501 Pedants celebrate the beginning of the sixteenth century.
1 January 1600 Almost everyone celebrates the beginning of the seventeenth century. 1 January 1601 People begin to get really fed up with pedants.
1 January 1700 Almost everyone celebrates the beginning of the eighteenth century. 1 January 1701 A few pedants begin to notice that pedants tend not to have very good celebrations.
1 January 1800 Almost everyone celebrates the beginning of the nineteenth century. A splinter group of ex-pedants turn up and get very drunk. 1 January 1801 The rest of the pedants celebrate the beginning of the nineteenth century.
1 January 1900 Almost everyone celebrates the beginning of the twentieth century. No pedants allowed. 1 January 1901 Pedants hold a Morris dancing festival.
24 November 1996 The Digital Village web site goes online: the third Millennium starts early and catches everybody by surprise.
1 January 2000 Anybody who even mentions the Millennium gets garrotted. 1 January 2001 Massacre of the Pedants.