At the 1st of April (fools day) Google made a worldwide 'joke' about visitors from a space station? Isn't that an obvious show up how they can manipulate analytics globally ? What do you think?
Of course that they can manipulate analytics , because is a service provided by them , but why would they do it?
If you don't want it to happen, don't use GA. After all, it is written in their license agreement that they are not responsible for inaccurate data (or for anything more precisely).