Yup. While it is true that allowing others to modify my work will probably bite me in the ass in the future, there are also some arguments for allowing this.
For one, the book is targeted to Filipino students - teachers may want to modify the names/scenarios to better suit their country. Sure, gives them a low-hanging trolling fruit (e.g. putting vulgar words in the i18n section), but I really don't have the time to review these forks.