Thank you for the multiple images. But they seem to all drive home my point: no matter how small the sign UP button is, it always appears at the same time the sign IN button is present.
Just like if the sign IN button was a teenager, that always needs to have its sign UP button chaperone present.
Or the sign IN button was your pet dog, who is not going out of the house without its sign UP button flea collar attached.
And the chaperone is not allowed any bathroom breaks, so must be present, visible, with the teenager at all times, and not just in the other room or anything. Even within earshot.