Simo Häyhä said:
It's okay but our IDs have that function I believe so.
§ 18 Player Names and Tags said:
(1) Players must play with the name they are signed up under in the team roster. If a player plays with a different name for the first time, he or she will be warned. For the second time he or she will be suspended for one match.
(2) Players must wear the team tag during official matches. If a player plays with a different tag for without one for the first time, he or she will be warned. For the second time he or she will be suspended for one match.
These rules were introduced to make it easier for both the casters as well as the viewers of streamed matches to identify players.
We also sincerely believe that it is possible for players to stick to the same nickname for the duration of a tournament.