Protecting the Trademark by Buying Domain Names

There are many companies that buy every related domain name on the market as a measure to protect their Trademark. Is this method a good approach?

Domain Name Registration Spam – Scam

Domain Name Registration spamming and scamming are more and more used by certain companies to make profits.
These scams make use of our misinformation, human weakness and public information on the Domain Registration to make us buy domain names at extremely high prices.