To have no strings attached means that there are no conditions or restrictions or obligations that must be met, but in this context there are a number of conditions that must be met in order for the wish to be granted.
Consider the statement "A wish that was only granted if a number of conditions or restrictions or obligations were met, as long as the judge approved it.". Is the statement "A wish with no strings attached whatsoever, as long as the judge approved it." false? Yes/no/unknown