[HOTFIX] Ignore invalid pages (not existing template)

But if they delete the template, the system is not going to work properly. If the user tries to access the node with the invalid template, its going to crash right?

It would be better, I think, to return a DummyStructure or something, which can be rendered in a special way in the frontend (e.g. navgation links to this structure would be inactive, content blocks would say "Invalid Content" or something).

And it isn't the "user" that deletes the template, its the "developer" :) The developer should know better and should ensure that the CMS is valid before shipping.