Street complete probably isn't the tool you want if you want to preserve privacy like this, people will be able to know where you have been. There is an option to turn off automatic uploads of answers however that will allow you to wait until a time you're happy to submit your changes, but this does increase the chance of change collisions.
A better workflow may be to just take notes with a GPS enabled voice notes tool, or similar and updating the map with one of the standard editors (ID etc) when you're back home.
If you're happy and you know it clap your hands!