Web service is not like ad on a paper or a public billboard. If service is being scraped by other companies who makes or not makes money for it, or prevents the

Web service is not like ad on a paper or a public billboard. If service is being scraped by other companies who makes or not makes money for it, or prevents the owner making money with it (filtering out the ads) this service is most likely to cause extra costs as bandwith and processing power. They are not free. So you should have right to block anybody from your site as you wish!