[michaelj3]

You're going to "rig up" an essential safety device like a lap or shoulder belt? Wouldn't an upside down milk crate be easier and just as safe? I guess you could always get the other families in your carpool to sign a disclosure acknowledgment and liability waiver, unless you plan to sacrifice your own offspring to the 8th seat.

Well said. My opinion is you should consult your dealer and see if its possible to add one to your vehicle as originally designed. If not, I don't think you should risk injury to a child who likely is not savvy enough to make their own call on safety.