Back in the day, 1980/90's......referees primarily wore black with either black or white collars. Long sleeve ref jerseys had white cuffs. I hated those white collars and cuffs because they were a pain to keep clean. I don't remember teams wearing black jerseys.
No where in the LOTG does it say that the referees must change jersey colors if there is a conflict. The LOTG do state what colors the teams wear and a team must wear colors that distinguish them from the other team and match officials. Most refs will not make a team change colors because there is a color conflict. This past summer I had to have a Beach, a Legends and out of state teamm change out of their yellow jerseys. I was not being an a-hole, but had a youth referee on the crew that only had a yellow jersey. This problem comes up often with the new referee's especially the youth refs. Ref jerseys are $30-$50 depending on the manufacturer and quality. Some of these new youth refs do not have the money to buy multiple jerseys right away after spending $150 on the course and all of the initial supplies. I just think it would be easier if there was one designated color of jersey for refs that teams could not use. Maybe bright construction worker orange?
LOTG Law 4 states:
• The two teams must wear colours that distinguish them from each other and the match officials.
• Each goalkeeper must wear colours that are distinguishable from the other players and the match officials.