Is grenade jumping a game mechanic that Gearbox intended for players to use? Evidence for this would come in the form of challenges/items which require grenade jumping to achieve, but this is tricky to determine, as just because I (for example) don’t know how to reach something without grenade jumping doesn’t mean that it’s not possible.
For example: one can grenade jump onto the rooftops in Sanctuary to get the Cult of the Vault symbols, but there are ways to run and jump to these locations, which is an argument against grenade jumping being done on purpose (while it’s faster, it’s not necessary).
As another example, consider the red chest in the Arid Nexus Boneyard over the third Eridium Pump Station; I can walk there on the pipeline from the first Eridium Pump Station without grenades, but cannot seem to get onto the actual rooftop with the chest without grenade jumping, which makes me think the game designers who put it there intended the player to use this mechanic to reach the chest. Alternately, it’s possible to get up there without grenades, and I just haven’t found it.
Grenade jumping: wonderful coincidence that the lift mechanic works and does not kill you, or built for a purpose?