Is leapfrogging a group to a camp allowed?

[mev]

Recently, my group was clearing the way to efreeti in SolB. We were pulling to the lilly pads and had cleared halfway to it. A group runs through our camp after we indicated that we were camping efreeti and clearing to it, and then they beat us to it.

I thought that
1) Efreeti was one camp, so they wouldn't have a claim on it if we we already at it, even if we were pulling to lilly pads rather than efreeti room.
2) Even if the only efreeti camp was in the room, leapfrogging over another group that was clearing to a camp was frowned on because otherwise there would be a strong incentive to wait around for a different group to start clearing something before you charge in at the last moment.

Is that not right?

The group was very gracious (when we tried to beat them at leapfrogging and failed, they rezzed us), but the experience as a whole still felt pretty bad, and they stayed there for hours.