I agree with all that in the sense that proper policing and security is what is needed. That's why I said only as a temporary measure until the security issue has been gotten to grips with....and I think it's a problem that goes beyond just individual clubs and is presently a shambles. The safety zone would be an interim measure while the security measure are put in place, whether that means hiring more staff, new training, new equipment, CCTV or whatever else. That's not going to happen at the flip of a switch, so the safety zone would be an option for targeted fans while the protection measures aren't in place.
As for playing behind closed doors, I think it punishes the good fans and still doesn't really get to grips with what happens once the terraces are open again. That said, I do accept that the financial drain it would cause might prompt clubs to act more quickly.