"Just lick it," said my wife, sitting in the passenger seat, holding up the plastic sucker. But as I eyed passing pedestrians, my mouth went dry. More on this exciting domestic stand-off shortly.

First, some background on why I wouldn't buy a GPS system for my car. There are two reasons.

Neither has anything to do with GPS products' navigation talents. I know a couple of confused tourists have bagged them on Fair Go, but I've found systems from Navman, Garmin and TomTom are usually very good at guiding me to where I want to go. Their 3D scrolling maps are a technological marvel, as is the voice coming out of their speakers telling you when to turn (I'm also enjoying the fact that my current test system, TomTom's $749 Go 720, comes with an optional widget that lets you play your iPod through its modest speakers, or route it through your car stereo via an FM transmitter).

Occasionally they do get confused. Say, by the New Zealand quirk that sees some major road names arbitrarily change after an intersection (Balmoral Road turning into St Lukes Rd in central Auckland is a classic for catching out GPS). But all the major brands are also very good, and fast, at recalibrating an alternative route to get you on track. The only duff brand we've encountered is Goldfinger (also bagged in Consumer tests). On the whole, I'm constantly impressed by the technology. (Read PC World's latest GPS group test here, and Scott Barltey's review of the TomTom Go 720 here).

Smash and grab
My first problem is that I'm just too scared. I'm completely serious here.

At TomTom's NZ launch back in September, I related how my sister-in-law just had her Navman GPS stolen from her hatchback - for the second time in months. This on top of one of Navman's new 'n' series systems being snatched out of our Reviews Editor's car while on loan for a PC World test. Scott had taken the trouble to always remove the GPS system from his car at night - and in fact it wasn't on its stalk when he ducked into a shop for 10 minutes - but when he got out a theft had smashed his window and grabbed the hidden Navman.

None of my lunch companions were surprised. The editor of another tech publication said he'd had a Navman stolen out of his car too. And a guy from Geosmart (the AA-owned company that sells maps to both Navman and TomTom ) said while his GPS system was not stolen, a wannabe thief had seen the stalk (the sucker thing that holds it to the window) and smashed his car window on a fishing expedition.

Wow. Admittedly my sample of people who use in-car GPS systems is not huge. But every single one of them has been targetted by a thief.

(Incidentally, only commercial systems used by truckers etc have a transmitter as well as a receiver, which would allow a stolen system to be traced).

With GPS systems priced between at $500 and beyond, it's not good to get one knicked. There at any ickky may-it's-worth-the-excess point for many insurance policies, and of course you've got to report the theft to the police to start the insurance process, and you'll likely have a smashed window to deal with too.

Suckers
GPS makers are quite aware of the theft problem. When I turn off my Tom Tom Go 720, a little graphic appears reminding you to take your GPS unit off its stalk and take it with you.

But the plastic stalk is my second problem. It looks ugly and intrusive in the middle of your windscreen (where it must sit to pick up GPS satellite signals). And for power, a chord dangles down to my car's cigarette lighter. It's a messy set-up, and my knee constantly knocks the charger (which you can dispense with once the Tom Tom's battery is charged).

Worse, to prevent a smash-and-grab fishing expedition like the one described above, you've got to pull off the stalk each time you de-car as well.

There are two stalk scenarios. One, it's plastic sucker falls off your windscreen, sending your GPS falling into your lap. This has happened to me numerous times. Or, two, you like the plastic sucker before attaching it to your windscreen. If you can get over the embarrassmentthis entails - or the self-esteem issues inherent in crouching below your steering wheel as you do it (which is where we came in) - then your GPS will stick fast. So fast that it's a pain trying to pull it off every time you park.

You can mount a GPS on your dashboard, but there's extra cost involved, and you're also likely to want to upgrade your GPS system at some point, for New Zealand lacks many associated services common in other countries, such as voice recognition - so you can speak the address of where you want to go, rather than type it onto your GPS's touchscreen - and GSM alerts about traffic jams.

Maybe my two issues are fussy and paranoid, but they're genuine, real-life roadstops that stop me buying one of these high-tech wonders