The IRS requires you to deduct all allowable deductions to figure earned income. That being said deductions are only allowed for expenses you can substantiate, so if you no longer have record of an expense it never happened from the IRS point of view. I think that if the IRS audits you and then sees you have no expenses for the business they will estimate expenses for the business. Since you are an Uber driver they will say if you earned money, you obviously drove miles. I also think that you taking this position would be fraud.