Drops While in a group

Does being in a group of NPCs affect the amount of items that are dropped from a mob?
What if they stand far away and don't fight?

http://wiki.guildwars.com/wiki/Drops

Will tell you everything you need to know.

The answer is: yes, heroes and hench take their share of loot too (problem is that their loot never shows up, so it is hard to tell).

However (and i think wiki isnt very clear about that) is the effect of heros/hench flagged far away (greyed out in party window)... in fow, uw and sorrows furnance are a lot of chest that always give a purple reward to ONE of the players when certain quests are completed (according to wiki that is loot too). I used to lots of spider runs for my heroes and some runs in SF (just for fun). When done i always flagged my heroes far away before opening such chest. That way the reward was always for me)... so i assume this goes for normal drops too.

Thats because its the official not so good wiki.

http://guildwars.wikia.com/wiki/Loot#Loot_sharing

The better wiki does say it however.Like Godh said,Henchmen/Heroes also get their share of drops,a party member however does not get loot from a monster if they were off radar/greyed out.