They can't, for several reasons, one we don't have that stand built yet, and two, government legislation is required to allow safe standing, and its still not on the governments agenda, and if you're honest they have bigger things to worry about currently.
I know. I meant in the future. The NS is in hold. The focus is now the Etihad Campus. 5 years? I would rather City wait until safe standing is introduced. It will be.