It's not "theme park", "water slide" or "lolly buffet": It's free Wi-Fi.

A remake of the beloved Roald Dahl tale, Charlie and the Chocolate Factory, would undoubtedly contain a Golden Ticket with the Wi-Fi password inside.

"Wow, free Wi-Fi. I give this hotel five stars," Taj enthuses, regardless of the surroundings.

As a former Luddite – and working class gal – I have indulged the kids' obsession.

Well, why not? It works! It's free! They play games for hours!

Of course, wiser heads are aware of the adage, "If it seems too good to be true, it probably is".

Which would explain the multitude of viruses we've contracted on our devices in recent months.

Public Wi-Fi in hotels, airports and theme parks is easy to hack using "sniffers": software designed to intercept and decode data transmitted over a network.

Hackers position themselves at the hotspot, collecting your information.

So how do you stop kids exposing sensitive stuff to criminals?

A cheap and easy way is to get a VPN, which stands for Virtual Private Network.

This encrypts all data, hiding your IP address.

There are plenty of free providers, but beware: some are proxy services, which aren't encrypted. That means your IP address is changed, but not hidden.

NordVPN has a cheap and easy-to-use service for both Android and Mac. Its app chooses the fastest server to connect to, in each country you visit.

A VPN also allows you to access banned sites, for example Facebook in Vietnam.

This is handy for teens who want to stay in contact with their friends.

You can access most streaming services – including Netflix, Spotify and YouTube – as if you live in the US, with no local restrictions.

As an added bonus, you can save money on flights. The price of airline tickets changes dramatically, depending on which country you buy them from. Using a VPN, you can appear to be in Africa or South America, to buy cheaper tickets.

"Good to see you're keeping up with modern technology, Mum," Grace says, as I explain how the VPN works.

I muse over their bravado. This is the generation that learns to swipe before they speak. But they're the most vulnerable online. Security company Symantec says children are responsible for one-in-five cases of hacking, by downloading a virus or malicious software to the family computer.

Concerns over safety when travelling with kids used to concentrate on physical threats.

Now, the virtual world poses its own dangers.

Fortunately, there are plenty of tools out there to put old-school parents' minds at rest.

tracey.spicer@fairfaxmedia.com.au