you could be right - but how can one tell? Without a personal recommendation, when your roof is leaking, you have to do something. Is fair trades unreliable?
I do always try to get personal recommendations, but it happened nobody I knew had used a roofer recently
My gas engineer is a hero, even gave my little sis a lecture on looking after her boiler and talked us through a water tank repair while he was on a beach in spain. Love him and don't care what he charges.