Needing without asking is a ninja on crafting materials as far as I am concern.
Ridiculous; if you and another person need it, then you both click 'need' and let the dice decide.
Nobody needs your permission to Need an item, and you don't owe anyone an explanation.
If this was not true, the Need and Greed mechanics would not be in the game.
On the other hand I know how touchy people can get. I once Needed a pair of Columi boots after taking a 2 month break from the game and didnt realise I already had a pair. Someone in my party did realise and said I was a ninja. I was affected by his rage: all I'd done was click Need - he also has a Need button. What's the problem?
Sometimes mistakes happen.