To my mind, there is no risk of conflict of interest because the employer is represented, in any case. I think port workers want the port to operate and might even provide interesting insights regarding productivity, efficiency and shortcomings. Listening to workers is always helpful for productivity and a company's success.
I support my colleagues who are asking for a seat on the board of directors. For my part, I am concerned that the union will be left out of discussions relating to working conditions, among other issues.
Nonetheless, I think it is always a good idea to have a union representative at the table to get insights from the workers; otherwise, a piece of the puzzle is missing. I do not see any risk of conflict of interest.