We shake our heads at the naivety of people fooled by Nigerian money scams and door-to-door swindlers (last year Aussies lost upwards of $680 million to such ruses) and wonder how anyone could be so stupid.

Well. Let me tell you about my $7000 balloon.

That's right. I paid $7000 for a garden variety balloon, the kind that embryonic PR executives and enterprising backpackers wave in the faces of frazzled mums at shopping centres each and every day. (And please don't get me started about this practice or you will end up having to smother me with a large pillow.)

Indeed it was precisely such a balloon that I took delivery of two years ago when my then baying toddler cried out for one from the cheery lady waving them about in a busy shopping mall.

(Parents are on a hiding to nothing in these situations: accept the balloon and you're almost certainly going to end up taking calls from financial advisors at dinner time until you die. Probably even after you die. Don't accept the balloon and you look like the sort of parent who would deprive their child of a free balloon, and no doubt food and shelter.)

And so I took the balloon and thanked the bubbly lady who proceeded to ask about my other children.

"Oh, a teenager?" she said, as though she too were harbouring an alien at home. "And how are her grades going?"

You know where this is headed, don't you?

I joked about how my teen kept her school work largely under wraps until report card time and about how I couldn't help her anyway with maths homework these days, certainly not since they stopped "carrying the one".

Inevitably I ended up agreeing to an in-home presentation from a mathematics computer-based tutor business, which I totally planned on cancelling. Inexplicably, I didn't.

The earnest young mathematics enthusiast (read: salesman) arrived at our home one evening soon after, a tad late because he'd had to call his kids and wish them goodnight on account of working back late.