Yes, your trips can be viewed by any ThrillPiXx user, regardless of whether they are following you. However, you can make individual trips private.
To make a trip private, tap the Private toggle button on the Create a trip screen or Edit Trip screen. A message displays, confirming whether to make the trip private. Tap the OK button to make the trip private.
Note: A toggle button that is grey and to the left indicates that the trip is not private. A toggle button that is blue and to the right indicates the trip is private.