Perform a thorough research on the observatory grounds before visiting the volcanic site. Also, ensure that you have a licensed tour guide from a recognized tour company to avoid being scammed by imposters.
Know the exact name of the location you are visiting if you are using public transportation means. For instance, you should only travel with the bus going to Parque Nacional and not be tricked to going to a different destination like Parque Ecológico.
Perform an investigation on the actual cost of traveling to the observatory grounds before starting the journey to the site. This will help to minimize the risk of being scammed by being overcharged for the same distance by scamming tour guides.