Would you sign this tax return?

Duncan Devious (age 52) is a self-employed attorney. Duncan loves to be noticed in public and, therefore, he drives a 7,000-pound, military-type, crossover SUV, the only vehicle he owns. When you are preparing his tax return, you notice that he claims 90 percent of his total auto expenses as a business deduction on his Schedule C and 10 percent as personal use, with total miles driven in 2017 as 10,000. You note from his home and office addresses on his tax return that he lives approximately 15 miles from his office. The total of the expenses (i.e., gas, oil, maintenance, depreciation) he claims is $31,200. He does not have a mileage log to substantiate the business use of the SUV.

Would you sign the Paid Preparer's declaration (see example above) on this return? Why or why not?