Any review system is prone to bias and discrimination — By Andrew Hill I like questionnaires, oddly, but I seem to have spent hours recently filling in or fending off requests for ratings and reviews. Over-eager Airbnb hosts, useless utilities, hit-and-run couriers, family-run hotels with a TripAdvisor obsession, airlines, restaurants, even public toilets, whose panel of germ-ridden grumpy-to-smiley faces is…