I would hardly call the coats of arms "scams" since they are so easily researched on other web sites. And are recorded in historical records.
I would think that anyone who believes that they would receive detailed and accurate information of their particular branch of a family from a source such as this is the same someone who believes the information relayed to them by a WDW bus driver.
I think the whole family tree/coats of arms is just great if you take it for what it is: for entertainment purposes only. When we did ours we laughed our heads off at the differences between our family history and what was given to us at the Epcot store. I certainly wasn't going to get upset by it.
Maybe you would have felt better about your experience if they had a disclaimer mounted for all to see. Something like "Your family tree and coat of arms revealed while u wait. Nah, we're just messin' with ya."