You shouldn't have any problems with the Zeromotive ignition cover. Unlike the Sazaire one, it doesn't also have a cover for the ignition lock cylinder itself. And that is where the issue lies with the Sazaire piece. That extra bit of material ontop of the lock cylinder can cause some keys from being pushed in far enough to rotate the cylinder.
The OE key with plastic grip is fine. But a basic flat OE key with no extra grip can be an issue. I trimmed my spare basic OE key with a dremel in case I ever have to use it.
And if you look at the key the fellow that had all the trouble was using, you can see it's an aftermarket key.