Goes against conventional wisdom, yes but both Matt and Joel reckon they'll be fine.
I'm currently at 67kg and my daughter weighs 27kg so should be ok for a while at least!
Hopefully, you'll see us piloting it up Layhams soon, either that or in a bloody heap!
For even more reassurance... friend's are racing the highland trail on their 29er tandem with 32 spokes at each end, they're probably about 120kg combined + 18kg of tandem and ~6-7kg of clothes/kit/water/food on top of that...
32 spokes is a bit low for tandem wheels no?