[pavbref]

Rule 7 states that a coach shall submit in writing to the scorer an accurate roster giving names and uniform numbers of all players. There is also a note that a player's number may change without penalty if the player must change uniforms due to blood on the uniform.
Rule 10-4-3 states that a player redesignated as libero must have a unique number not worn by any teammate.
Rule 4-2-3 states that each player must be identified by a number on the uniform top which is not a duplicate of a teammate's number.

Combining these rules implies that the team you specified has violated the rules and exhibited bad sportsmanship. Rule 4-2-3 is the primary reason. The players are now wearing numbers that are duplicates of teammates.