Over the course of the head-start weekend given to Guild Wars 2 players
who pre-ordered the game, a player from the French guild War Legend
reached the level cap by crafting, using materials donated by his guild
members.

The player, whose character is named Surfeuze, played the game normally
up to level 60. The final 20 levels were gained by crafting. This is
according to a statement made by the War Legends Webteam:

Due to some rumors about an “all craft levelling” plus Mike
O’Brien’s message about “abnormal leveling” on reddit, most people seem to
think that the achievement isn’t legit, so we’d like you, if possible, to
explain that the fisrt 60 levels were done in “classical” PvE and without
any “exploit bug” or “cheat”. Only the lasts 20 levels used crafting, we
didn’t use WvW either.

ArenaNet has investigated the claim, after suspicions that Surfeuze was
one of many players using an unnamed leveling exploit, and has confirmed
that the achievement is legitimate, done without exploits. They
even congratulated him for it.

Source: MMOCulture