Even if it is possible to legally have the same OT name, ID, SID, language and region as someone else or as an event, this is over 200 bits that must be equal hence this cannot possibly happen unless you are trying to do it deliberately. Any nickname change that happens on a different game than the original is hence a deliberate break of the game intended mechanic on nicknames. Even if it's allowed by the game (because there's no better way to be sure a Pokémon is yours originally) any breach of this rule should be considered as deliberate hacking. Furthermore, if you consider this practise legal then every default trash byte string is valid on pal park and events. What you are asking is making a huge number of hacks legal just because you want to renickname events or traded stuff, which in itself should be considered hacking.
Furthermore I don't know where you get your info on trash bytes but they're wrong. Sid 0 is legal, Eigakan Arceus has all \FFFF trash bytes, a kyurem with Ash\FFFF\4300\4100\0000\FFFF as trash bytes will get a clear warning the trash bytes are incorrect.