I have a friend who is so irritated by advertisements breaking into his TV sports viewing that he has vowed to boycott those advertisers' products. Has anyone studied negative responses to advertising like this, or the possible negative effect of sports-shirt sponsorship?

Certain soccer clubs - Real Madrid and Manchester United, for example - are intensely disliked by more people than actually support them. Has sponsoring such a team ever damaged sales or the popularity of the firm whose name appears on its shirts?

Alan King, Liverpool, UK

Surely for the level of accuracy it seems to offer, it would need far more cameras than appear to be present at major tennis tournaments. Yet everybody happily accepts its rulings. How does it work?

Franco Pallatini, New York, US