The FAQ says the data usage is 200 kB per hour. So maybe it won't be constantly checking the location and therefore won't impact so much on the battery.
A metre accurate location using a UTM projection would require less than 64 bits.
20 bits for Easting/Westing, 25 bits for Northing/Southing and 6 bits for the UTM Zone.
Which is only 51 bits, add check values and you are getting it into a handful of bytes, and that is for global, rather than Switzerland only.
For Switzerland only you can delete the UTM zone and use zone 32, and add one extra bit onto the Easting/Westing figure.
So that takes us to 46 bits total.
48 with a pair of check bits. Or 6 bytes.
Excluding headers, you would be looking at 22kB/hr to check it every single second
So it looks like it does check continuously.
But we should definitely have a similar system in the UK..... and if it could be tied into free WiFi on trains it would enable checking what train the phone is aboard.