On iOS, Android, and Mac this is handled automatically and every app will have its own data. On Windows, and Linux it uses the exe to differentiate apps, so you are right, if we both had an app named Fish they would go to the same folder. We initially had it use the full exe path to differentiate apps, but in some cases this generated paths that were too long for Windows. So there is probably some room for improvement here, however since the paths are set up before the bytecode runs it is difficult to get the app to provide a unique string like a company name or something.
For now if you are using a common exe name then it might be best to use a unique folder inside the write folder when writing files. For example OpenToWrite("/MyCompany/MySaveFile.txt"), or using the SetRawWritePath and MakeFolder commands to create a custom folder in the AppData folder and then setting your write path to that.