We discussed this before, but I thought I'd summarize for anyone else who notices the same thing.

The problem is that checking whether a service is enabled or not isn't just "yes" or "no", since all services can be enabled or disabled for all members, guests, and those in custom member packages.

Now is where it gets complicated: when you aren't logged in, the website will have no way of knowing who is going to login, and therefor can't know whether it should show the stealth login option or not until you are logged in (since it can't tell if the service is enabled for your member type until it knows who you are).

The best solution I could think of was just to check if anyone has the ability to use stealth mode or whether it is disabled for everyone. If it isn't disabled outright, it will show for everyone, otherwise if it is set to "no one", then it will never display.