Forget mortality risk it is irrelevant so whether someone is in an at risk group is neither here nor there. Forget liability too difficult to prove even if the club took virtually no mitigating measures.
However the stumbling block is and always will be risk of infection posed by crowds (even reduced ones). The secondary consideration is that big random crowds quickly overwhelm any effort to track trace and isolate infected people.
I think dispersal might be an issue, & I still think it's doable, but the cost to police & manage it safely might make it prohibitive.
The problem is Stan, as we've said previously, if you can't get revenue from the fan base, where can you get it from?
I was listening to Chris Whitty the other night answering a question from Robby Savage, Prof Whitty suggested that the game itself might have to be modified to minimise the risk of cross infection.