The Robert / Bobby issue is one more example of discrimination in the application of airport security checks. People with foreign nicknames that are extremely common but unfamiliar to the insular TSA line personnel have trouble when the names don't match exactly. Robert travelling as Bobby goes right on through.
A relative of mine had to change his name legally to his nickname from his given name because of the continual recurrence of this dilemma. Half of his official paperwork was in his given name and the other half in his nickname.