I think the only answer is: "I don't know".
If God was able to and did disappear, I assume I would not be here.
But if I was, I am sure I would notice.
Even if I wasn't here, it's not to say that I no longer 'am'.
And I still happen to 'be', even if I am not 'here', there I would assume again that I would notice.
But if God disappeared and I was no longer here, there or anywhere, then perhaps I would not notice.
I do not know how Gods powers work; I just believe there are none stronger.