Bob was often known for accompanying different hunting parties out on their excursions, He was seen as an extension of their Lord's will, as the people understood him to be the Lord's son instead of Seth's.
Thus, when he was gathering at the gate with a group of relatively unknown people, who were clearly gathering for an expedition of some kind, little was thought about it. It was just another hunting party, they assumed.
It was this assumption that they were playing on, and part of the reason they took this choice of party members. The other reason towards this parties make up, was because of their abilities and their unnerving levels of loyalty.
