Adwords Advantage - commercially and legally sound or not?

It is common for business owners with a strong on-line product offering ("Advertiser") to purchase an Adword advertising campaign through Google Inc to maximise their exposure on the internet.  Through a method of search engine optimisation, the Advertiser can elevate the position of their website link when a potential consumer undertakes a keyword Google search.  The keyword search is the Advertiser's link to the consumer and by causing the consumer to open their link first or at least, for their advertisement/website link to appear on the first opening page, the Advertiser hopes to secure a sale from that consumer.

In some cases, the Advertiser has attempted to obtain a business advantage over a competitor by using the competitor's trade mark as their key word in the AdWords campaign.  Google Inc will not query ownership of the keyword nor whether the action is legal.  The Advertiser signs an agreement with Google Inc which will ensure the Advertiser's  compliance