Illegal Pokémon safe in Home?

[Eggs]

Hello again, my friend just got his first Switch Pkmn game and wanted to know if anything bad would happen to the illegal mons he genned during the 3DS era if he were to move them to Home? He's only ever used them offline since we know that bringing them to any online feature would get the ban hammer dropped on him. We also did a bit of googling and found that badly genned mons turned into Bad Eggs that permanently take up a slot in Home so he's mainly afraid of that happening. For the record, the mons he has aren't like permanent Megas or mons w/ illegal moves, they're mainly legit ones that have been tweaked a bit aesthetically(?) e.g. he got an Ash-Gren from the SuMo demo but used PkHeX to turn it shiny and changed the OT, TID, and SID to match his own.

Edited February 11 by Eggs

[SkyLink98]

The golden rule is never use illegal mons online.
Home is a server-side application, hence figures as an online service.

History shows that GF/ILCA/TPCi can turn illegal mons into bad eggs anytime if they want. There were also some rare, but still present, ban scenarios for mass-transfering illegal mons in Home.

In the end, do at your own risk. Maybe he won't be flagged, maybe he will. We can't say for sure. Is it worth the risk?