Back in the day (don't ask how far back) I used to help guide a backpacking trip or two. If we had two guides and the terrain was non-technical we always ran one guide at the back of the pack. An experienced eye at the back of the pack can see a LOT of trouble before it gets out of hand.
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"There is not a man of us who does not at times need a helping hand to be stretched out to him, and then shame upon him who will not stretch out the helping hand to his brother." -Theodore Roosevelt