Guild bounty hunts
Although the Guild Bounty system needs a LOT of work, I don’t think this is one of them. Any good guild leader would have pre-read the details on this event, and let everyone know WELL in advance that they NEED to get ALL waypoints in the zones that are possible boss zones. We have a few in our guild that don’t have all their waypoints yet, and they know that they have to hoof it, or miss out.
Since the guild bosses scale based on how many you have there at the boss, as long as you had 5 at the boss, I highly doubt this is the reason you failed the event.
Getting waypoints is not something that needs a guild to accomplish, and with a little time and determination, anyone can do it solo. Having a friend to help out is a BIG help, but not necessary. Grab a buddy for an hour or so each day, and go tag waypoints, even if you skip the other stuff in the zone for now, you can easily recall there and get it later.