I've been worrying about how I'm going to ride with Samuel and Shira when Shira gets too big for the Ibert and this is the solution. We got the child attachment for Samuel so that he can actually pedal and reach the handlebars, and made it a triple by adding the tag-a-long for Shira. 
It's not perfect; Shira isn't quite big enough for the tag-a-long yet, but we made it to the market and back without anyone falling off.
I did have a concerned citizen on a bike follow me for a few blocks though, telling me how I should tighten Shira's bike attachment. Blah, blah, blah. No one would ever tell a guy how to attach his bike components.
