Lord_Majestic - 4:21 pm on Aug 2, 2007 (gmt 0)

Webmasters can set rules by denying access to anybody they want

Indeed. And, in turn, search engines can set rules denying listing to those who try to game the system with cloaking.

It therefore becomes a question of who needs whom most - a webmaster wishing for free natural traffic from (say) Google, or Google having few pages less from billions available.