"I have recommended placing the vehicle under the business in future years"

Sched C means there is no "business" name to register this under. It's a disregarded entity. Putting it in a business name, if this was operating as an S Corp, would make all personal use taxable to the user through payroll. It is not always advantageous to register a vehicle to a business. It depends on the facts and circumstances. Now there are two vehicles in use for the business, and you still believe none of the use is personal?

"appears IRS has their ways of validating if the need arise"

Well, they don't have spies around town writing down license plates. They would require evidence, or they can deny a deduction being claimed that is not substantiated, if that is what you mean.