The Armor Assumption

The Armor Assumption; if you are outside a group of people, you assume that they own the most visually obvious item associated with their fan group, regardless of the way that item is often too expensive to buy, too time-consuming to make, too space-occupying to keep around, or too inconvenient to wear on a regular basis. This is because stereotyping people as "mostly 20 something males wearing t-shirts, and a lot of them wear glasses or have fairly nice phones" is really not very visually exciting.

For example; the same way all furry fans wear their very best fursuit to get buffalo chicken wings with other furries, all SCAdians own full suits of plate armor (hence the names).