I think the only conceivable way to limit trolling is to have some kind of punishment or accountability - what that could be I wouldn't be able to say (ban from SB events or SB disc would probs make most sense). I'd say individuals would be more likely to hold off it was their clan rather than them that would take the heat, but it's open to the public so that's not possible.
As for the point x makes above about people name changing - why can't the list of names taken for the CC account to add be used to put a discord acc against the username, which could then be used for any 'punishment' if said username trolls. Just don't allow last minute additions without them joining the regions discord and entering their username. It might not stop a double name change done last second, but would certainly limit the whole thing. I think there's definitely steps that can be taken to limit trolling, but they would all add a fair bit of overhead to the SB ranks organising and administrating it.