What the term "Traveler" means is that they are Spirits mainly of the dark or Purgatory Levels that have been released to travel about the Earth. These types of Spirits are released if they have earned this "pass" so that they are encouraged to become more involved with the Earth and to plan out their future incarnations along with whom they may want to be born to. They are encouraged to visit various continents, see various cultures and religious beliefs, etc. just to sample how it would feel if they were to be born in that land.
This plan of allowing these "Travelers" does work overall, and yet these traveling Spirits are not always intending to be doing good. They are monitored to a minor extent, yet that seems to be where the Guidance Guild is overwhelmed at the current time, which means that they are struggling right now to be supervising these Travelers to a point where we here on Earth are needing to be more cautious now. With so many Travelers out these days from Purgatory being overcrowded, that is why it is especially important to be noticing if there are any differences in how you are sensing Spirits or if you are feeling like you are dealing with someone in Spirit who is not feeling of the Light and saying things that differentiate with what you know to be right and true.