Because there is no reason why another web hoster than the one your website actually sits on would need to browse your website, because it will occur and it is simply some bots and hacking script crawling the web in a search of a security breach, here is a list of the CIDR ip address ranges that can be added to your .htaccess file to prevent unwanted access from major hosters on your site. Be sure not to block your own hoster.. or at least not the ip address your website is hosted on; because in fact, another server from the same web hoster you are actually could still possibly scam your website.