It would be hard to do this for a coal company because few coal companies deal too directly with the consumer, and even people who buy charcoal to grill with at

It would be hard to do this for a coal company because few coal companies deal too directly with the consumer, and even people who buy charcoal to grill with at home often do not get too attached to one brand since charcoal is close to being a commodity (yes, there are some people with strong opinions on this, but most people do not have them). But I suspect you will find this in every field where a consumer will be highly invested in the product, and especially in fields where their use of the product can be publicly seen, and even more so when it is publicly seen and thought (rightly or wrongly) to say something about the user. Many people are very proud of the type of car they drive. Most people who ride motorcycles have very strong opinions about the different brands and styles available. Many people (certainly not all, but many) who drive a Prius do so as much because they think it says something about them as for any other reason. As others have said, people will find different forms of tribalism in just about any public activity.