Not in Lion 10.7.5.... even if the guest user is turned off in Users & Groups by me, the administrator, the guest icon continues to show up at log in. If you choose to log in as "guest user" you are presented with a dialog box that says
"This computer will restart to a secure Safari-only system for the Guest User."
It then goes through a restart, which is slow, and the "guest" has access to Safari. Guest User can then get into their email accounts and open any emails. I tried to download an attachment but couldn't...thankfully!
When the guest leaves, his options are to shut down or restart, not log off, which is another time consuming process before the owner of the computer can log in.
To add this unnecessary, unavoidable interface takes away from the fluidity that was available to me when I purchased this Mac.
It's clumsy and it's garbage. Mac is loosing its focus.