Lacysboy

Hello - My first time. I plan to tow a very small utility trailer with my 2005 outback wagon. However, the guy installing my trailor hitch has offered two options for the wiring of the harness: 1. Attach to existing wires at rear lights. 2. He recomends attaching power to the battery itself - quite expensive. My question: Would using step 1 be ok considering I'm only drawing from the tailights? There would not be any other lights attached.