It is set to be the next big thing for gadget lovers everywhere - but users of Google Glass, a high-tech pair of spectacles with in-built hands-free video camera and internet access, are being given some basic advice: Take them off when visiting public conveniences.
Some attendees forgot to remove their Google Glass during calls of nature at a Google developers conference in San Francisco. The device has already raised privacy fears because it can record video far less conspicuously than a handheld device and could make it difficult for people to know when they are on camera.
Drew Olanoff, reviewing Glass for the Techcrunch website, said: "In its current state, Glass is a utility that allows you to do some of the things that your smartphone does now. The difference with Glass is that you can do these things hands-free, quicker than before and in a less socially disruptive way.
"Still, we heard about people wearing Glass in the bathroom, as if to remind us that not everyone is ready to feed into the hype of the device."
Alex Roth, a technology reviewer for Techradar, said: "Google is actively trying to reduce the voyeur factor by making it rather obvious when Glass is engaged. The screen emits a glow when in use, and spoken commands like 'take a picture' make sure those around you are clued in to what you're doing. You also have to look up to read the screen, so broken eye contact will be a dead giveaway. Your friends will know when you're checking football scores instead of listening to them. It also suffers a similar stigma to the Bluetooth earpiece, in that it's distracting, and a bit goofy looking."
Google executive chairman Eric Schmidt dismissed concerns about privacy during a talk at Harvard University's Kennedy School of Government in April, saying: "Criticisms are inevitably from people who are afraid of change or who have not figured out that there will be an adaptation of society to it."
Google Glass is supposed to perform many of the same tasks as smartphones, except the glasses respond to voice commands instead of fingers touching a display screen. The glasses are equipped with a camera and tiny display screen attached to a rim above the right eye.
Users can speak to the glasses as well as record video, access email, get driving directions and surf the internet by connecting wirelessly to a user's cell phone.
Google Glasses have yet to go on open sale but are being tested by a selected group of users in the US. The company also sold an unspecified number of Explorer models to computer programmers last year. The finished product is expected to cost around £1,000.
Nick Pickles, director of privacy campaign group Big Brother Watch, said: "Google Glass doesn't just challenge our assumptions about consent, it challenges whether we even have a choice any more. It makes it seem perfectly normal to collect data on other people, without ever asking their permission and that is a dangerous step that poses a fundamental threat to our current notion of privacy. People wearing Google Glass don't own the data, they don't control the data and they definitely don't know what happens to the data. This is turning members of the public into a Google army, collecting data for the sole benefit of selling advertising and boosting Google's profits."