I don't think it's the staff's fault, but I had my backpack open (and one thing went missing) while it was in the luggage room after I checked out. I think only staff should be allowed in that room.
I enjoyed my stay at Papaya Hostel. The staff is incredibly helpful and you can see the owners planned the hostel very well before building it. I was surprised there were no lockers in the room, I suppose they're working on it. The hostel is three blocks away from the main street.
Excellent hostel. I think you should consider allowing guests to check-in before midday.