'Given the chance any middle-aged tourists will behave like 10-year-olds'

I BELIEVE that in any given tour group the brains of 93% of people turn to mince within 10 minutes of starting to gather. A corollary is that given the slightest chance any group of middle-aged tourists will behave like 10-year-olds.

Evidence? Three weeks in that wonderful country New Zealand, book-ended by spells in Hong Kong, Sydney and Singapore.

We had a great time at our own car-hire pace and inclination, but also realised as the happy weeks went by that we were ticking off most of the "things tourists do".

So what, we enjoyed it. Whale-watching at Kaikoura? Tick. Sydney Opera House? Tick. Adventure activity at Queenstown? Tick. Doubtful Sound overnight cruise? Tick. Picture taken at sign outside Dunedin railway station noting 'Edinburgh 18,467km'? Tick.

Much of this activity was necessarily in groups. As at the meeting place for a tour of Sydney Opera House - even better inside than outside to my mind - where Leane, our guide, said: "We're taking two tours at the same time today. Those of you who have a ticket with a stamp on it, go with Michael."

Panic and baffled moans as people who had spent a lifetime making sensible professional decisions, raising families and being pillars of the community ran up to Leane and asked pitifully: "Is this a stamp? Is this?" She was obviously tempted, as a genuine Aussie, to reply: "My oath! No, THIS is a bloody stamp." Instead, she calmed them down and soothed their fears. Several still managed to get into the wrong group, not counting the ones who got lost completely.

We had the same trouble in Singapore where 14 out of 38 didn't even make it to the bus, while in Hong Kong the wily old sampan owner simplified matters for the most addle-pated by refusing to dock until we coughed up a landing fee.

When we gathered for the cruise of Doubtful Sound (a place of wonder and enchantment) a gourmet packed lunch was part of the deal, intended to fortify us for the long bus journey to the boat.

Within minutes of collecting their lunches in mid-morning, most of our fellow-tourists were wolfing into them. It was like a school trip where children have their sandwiches unwrapped before the driver starts the bus.

Looking for adventure at Queenstown we noted that no one over 22 was bungee jumping and ruled out four hours of white water rafting. But we were brave enough for jet-boating. So were 16 others and I have the photographs of us grinning and waving like football fans who realise they're on camera as we rocked and spun. When another jet-boat passed in the opposite direction we all waved and cheered.

Now, of what does the hot flush of that memory remind me? It reminds me that once in Boston we took a tour on the DUKW - amphibious Second World War vehicles, painted brightly and adapted to gullible visitors - on which several dozen otherwise sane grown-ups were urged to bawl "Quack, quack!" every time two DUKWs passed each other. Do those others still wake sometimes in a cold sweat and think: "Did I really do that?" Oh yes. Make that brains to mince 100%.