Given the way the app works, the biggest fear of government misuse of data is probably that they will use it to enforce social distancing rules. Ironically, those who probably fear this sort of misuse of data the most, are the ones who it is probably most useful for (those who are likely to break social distancing rules). Perhaps the question should be of those who mistrust the government, are you already wilfully ignoring social distancing rules? If not, what have you got to hide?
I live under no illusion, that most of us, are probably revealing more about ourselves here on AFF than this app with safeguards in place.
[rant]I also find even more ironic that people are taking to twitter and facebook to vent about it and that they wouldn't trust the government, whilst willingly baring their whole lives via those said channels to private corporations based in the USA. Who do we trust more, the government we can boot out at elections, lead by a PM who can booted out even between elections, or a money making private company who cares nought for us, other than our potential to generate profits for them?[\rant]