I can't be bothered to read through 5 pages to see if someone else has written this, so I'll just post it anyway:
McLaughlin is within the DL rules to run, as the meeting has a local or global wildcard, and thus Brussels has decided to grant Sydney a global wildcard.
But, most importantly, it is a 'winner takes all' scenario...if she wins either/both events, not only is she crowned DL Champion...she gets a wild card for those events in Tokyo.
The defending World Champions are Jackson & Paulino....i.e not American, so the US can use her DL Winner status as a wild card & enter her for those events in Tokyo (assuming a) she starts and b) she wins..). This means at the US Championships next year she can run just the 400mh, safe in the knowledge she has wild cards for the 200m & 400m...and keep us all guessing as to which event/s she will run in Tokyo 25.
And there it is. The REAL reason why she may run both events in Brussels.