Is my GPS allowed in Switzerland?

(Decided to make this an answer)

The Swiss position on radar warning devices is here, and it states:

Radar warning devices (radar wave detection devices, radar detectors, driver-alert systems, etc.) alert vehicle drivers via acoustic or optical signals to police speed traps. These signals allow drivers who are driving too fast to reduce their speed in time before they reach the speed trap.

In Switzerland it is prohibited to use devices of this nature as well as to place them on the market.

But it is so vague¹ that it would seem that the Tom-Tom functionality is forbidden. However in doing some internet searches, the main topic that keeps coming up is "radar detectors" being illegal. These are effectively radio receivers that operate on the police radar band. And that is not what the Tom-Tom does.

However, they also do state on that page:

The Federal Roads Office (FEDRO) can provide you with information on the permissibility of individual device types.

So if you really want to be sure, you should contact the FEDRO and ask for their determination. However, IMHO, you should be OK with your Tom-Tom - just don't go showing the police the wonderful warnings that the device can generate.

^{(1) The page I linked to is in English, but I did not look at any of the equivalent French, German or Italian pages. And I am not sure what the official language(s) for laws in Switzerland have to be published in. So it's possible that the English translation isn't entirely valid.}

It should be OK, if you do not activate such service, and often GPS ask you explicit to use it (when travelling in some countries).

The device is not a problem. We use often phone to navigate, and all connected phone can potentially advise you about radars. And we know where the fix radar are placed (and I'm in a canton where the police must advice in advance where radars will be places (but with exceptions), and also radio tend to advise you about them). One strategy that police have is just to move frequently the position. And also they may use radars from a moving car. So now it seems also no more a concern to police (in past it was much more a concern, and so they tried actively to stop it).

So: you can use any GPS devices which have disabled the "radar service".

Just do not speed up too much. There is a low margin before the speed-up can be considered a crime (and not just a traffic penalty), and so handled with normal justice and so much more discretionally, and fees.