Blue Valkyrie
Not seen such Bravery!
Absolutely more than they could do normally !Nothing more than they could normally, they could choose to invade the pitch at any given time and get a game abandoned, any fans that do this such thing would see their club reprimanded including a potential points deduction that could put them back in trouble. We do however I think have to trust fans to behave, the vast majority are behaving now by social distancing I don't see how some behind closed doors games featuring these teams are going to turn them into complete loons.
You said that the behind closed door tournament would be stopped part way through if fans turned up in large numbers.
A great tactical way for them to finish the league at the exact moment their team has crawled out of the relegation zone.