Plain folks is a technique that attempts to put an idea, candidate, or product on a level of neighborly intimacy. "I may be a rich movie actor, but I'm really just like you, John Q. Public. And to prove it - look, I like old pickup trucks."

Explanation:

Anytime when people or companies try to portray themselves are "regular folks" or try to say they are "just like you."

Examples:

(i) Bread commercials that show Grandma's kitchen with wholesome ingredients lying on the counter. Grandma is wearing her apron as she removes a lovely loaf from the oven. All the while they are implying that their bread is made in this fashion rather than in a giant factory where huge trucks bring the ingredients, and machines do almost all the work.

(ii) Political candidates who wear blue jeans and eat chicken dinners after following Farmer Brown around the field.

Proof:

Show that the "folksy appeal" is a misrepresentation - a false appearance.