Assassination Robots
Semiapies: I think your premise is wrong - constant surveillance did jack-all to prevent this assassination and will continue to be little deterrent.  Surveillance doesn't often detect crimes/attacks before or even during their commission.  It's primarily good for piecing events together after-the-fact.Until behavior-analysis and/or facial recognition become ready for primetime so that a hotel security's gets an alert saying, "possible organized covert activity by these people", such operations will only continue.