I understand Tristan's point. Way back in HS I gave up some work time so I could participate in a car wash fundraiser for choir. We were thrilled with the total amount we made. Then my mom asked how much that would be per person to offset travel costs - and it turns out I only earned 1/2 or 1/3 of what I could have made if I went to work.
Now in the productivity and cost equations, suppose the piggy-bank-stuffer was doing it while at work ...
