Excluding topics from your output can create dead hyperlinks. If there are links to the excluded topics in other topics, those links will not have any targets and will produce errors or do nothing when the user clicks on them. You need to plan your project to prevent this from happening.
Help+Manual has several functions that can help you to prevent and eliminate dead hyperlinks caused by excluding topics. If you use them correctly you can easily locate all potential dead links and automatically replace them with alternative text or links.