Shelby was also in the London 2017 5000m final but got back to focussing more on the 1500 in 2018-19 anyway. She also ran several DL and other international races in 2018, so this was an exception from the Schumacher regime, apparently.
Anyway, let them do it, if it works. But one can hardly expect Rowbury or the others who are running to stay at home only because the BTC stay at home.