Absolutely, positively. So many people neglect the bearings and brakes on their trailers, and when they fail, it's always when you're hauling a load and in the middle of nowhere.
I saw a truck yesterday driving towards me, and it caught my eye from way out in the distance because he was leaving a trail of white smoke. As it got closer, I saw he was hauling a car, and the smoke was coming from one specific wheel on his trailer. I'm thinking stuck brake or seized bearing. Poor guy had no clue.
....should've turned around and alerted him, but I was almost home and had to pee.
@ProjectBazza In addition to those side markers, I recommend buying a roll of that DOT C-2 reflective tape. I put that stuff all over my trailers. I'd rather my trailer look like a damn Christmas tree than invisible.