"The other refs let me do it"

[joseph2493]

Your watching varsity pregame when you notice one of b's players is wearing a bright red undershirt.

Now this would not bother me, but the team jersey is blue and white.

During coaches conference I inform the coach that the undershirt can not be worn, because it does not match the uniform.

He informs me that all the other refs had let him wear it.

I told him that I could not let him wear it.

He says how come I couldn't let it go when everyone else has let him wear it. . .

Now I understand that coaches will say this just to try to get the edge on you, but what would ya'll suggest is the best way to address the statement, without belittling your fellow officials?