The robots.txt file of Youtube consists of numerous directives designed for the interaction of web crawlers. Predominantly, these directives encompass Disallow rules, which serve to limit crawling access across specific URLs. To exemplify, there are conditions such as Disallow: /feed, Disallow: /channel//featured, and Disallow: /feed/comments which restrain all user agents from accessing the respective paths. However, it is worth noting that Youtube does leave certain areas accessible like Allow: /channel//videos, Allow: /watch, and Allow: /results. Consequently, the robots.txt file spells out the paths which are accessible alongside those that are off-limits to crawling.

While Youtube does set restrictions on web scraping activities, it does allow it under certain conditions. Worthwhile paths for scraping like video details are found under paths like /watch, /results, and /channel//videos provided YouTube's guidance in the robots.txt file are followed. The disallowed routes typically constitute feeds, user-generated content, and comments. Hence, from a web scraping perspective, while not absolutely inviting, it is partially accessible given the adherence to the restrictions outlined in the robots.txt file.

YouTube's Terms of Service heavily restrict the use of automated access. Under the section 'Permissions and Restrictions', they clearly state that 'you agree not to access the Service using any automated means' and specify activities like scraping/crawling/data mining as prohibited. It also prohibits using the service for 'commercial uses'. Thereby, any form of automated data collection, including web scraping without explicit written consent from YouTube, is clear violation as per the terms. Notably, YouTube also imparts the 'right but not the obligation to monitor and edit or remove any activity or Content'. This implies that they actively monitor for any such unauthorized activity and reserve the right to take stringent actions against violations. This could include but is not limited to immediate account termination and IP blocking, hinting at their robust security measures. They also suggest that any technical attempt for access must be through the defined legitimate means, such as official APIs, maintaining user-friendly request rates, and proper identification of client applications.