It’s not such a dumb idea.
I once hired a contractor at the urging of a friend of mine. The contractor was the friend’s brother. The friend, who had been in a number of businesses over the years, including remodeling, promised that he would act as an unpaid overseer to make sure the work was done properly.
I met the contractor at the brother’s place of business. When introducing him, my friend called the brother by a different last name than his. Being too polite for my own good, I didn’t inquire further, assuming that perhaps they were half-brothers with the same mother but different fathers.
When it came time to sign the contract, which the contractor didn’t seem all that eager to provide or sign, I noticed that the address and telephone number were for my friend’s business. When I asked why, my friend replied, rather sheepishly, that it would be easier getting in touch with his brother through him. (These were the days before cell phones.)
The bottom line: The reason my friend and his brother had two different last names was that his brother, a veteran contractor, kept changing his name to avoid disgruntled customers, unpaid subcontractors, and angry suppliers.