Custom php Code for Panels visibiliy rule

E.g. there is a content profile type called hobby

I am using panels and settings are to show a tab for ever piece of panel content.

When you visit the user profile, you will see the hobby tab, although the node is not created yet.
This is not the edit tab, but the view tab, because it is not one's own profile.

So, one possibility would be to make a panels visibility rule using php code to check if the node is created.
Only when the node is created show the tab.

But I don't know how this php code should be.

Does someone have an idea?

I can't imagine another solution to hide a content profile tab for not yet created tabs.