They're probably claiming the entire truck as a business expense because of the wrap. Therefore, they're able to basically buy it with untaxed money, saving whatever their effective business tax rate is on the $100k or whatever. Of course, stuff like that is usually a bit of light tax fraud, because many small business owners just want a big expensive truck, but putting advertising on the car you drive for personal use doesn't make every mile a business mile. You can deduct the wrap itself, and if you are diligent you can deduct a reasonable and justifiable amount based on the advertising value and actual business use, but especially for shop owners, this is just tacky business owners hoping they don't get audited.

They probably think "tax deductible" means you take the entire value off your taxes or something.