There are, of course, shades of grey to Business Casual. Each industry has their own "norm", too.
Ad agencies are typically more hip and trendy.
The automotive industry is all about casual dressing. GM's updated dress code simply encourages employees to dress "appropriately". Ford's "relaxed business casual" policy states that employees must use good judgement and dress appropriately for the business environment and work requirements. That means that "business appropriate jeans" are allowed except when meeting with external contacts, dealers, suppliers and potential employees. The next question is what jeans are appropriate? At Ford, they must be hemmed, not frayed, faded, worn, torn or stained. No studs, decorative stitching, bling or rhinestones.