Tourism

Tourism is travelling to another region in Pokémon just to go sightseeing, instead of Pokémon catching and taking the challenge of gyms, island challenges, or tournaments.

In-Game Examples
When you first arrive to Hemphir, you are asked by the person at the desk if you are a tourist or a Pokémon trainer. When your mom says you and her are trainers, you are both required to show the person behind the desk your Trainer's Badge, which is proof that the holder can catch, study, and train Pokémon. Some regions only require the Trainer's Badge if the first part of the challenges contain newly discovered Pokémon (any fakemon). However, some, like Versol, require the Researcher's Badge. If you do not have either of these, you will be registered as a tourist.

You can register as a tourist and visit Versol before you get the Researcher's Badge. You can leave from one of the four airports in Hemphir. However, once you get the Researcher's Badge, you are able to travel Versol, catch Pokémon, and join the Versol Tournament.

Trivia

 * You cannot move to other regions. Going to airports and saying you want to move will require your mother's consent. It is impossible to ask your mom this question.
 * Even if you were moving, as some NPC's mention, moving to another region is oddly still referred to as tourism.