This question asks for the experimental result that is theoretically expected or is know already from experience, when one considers the following two scenarios for the micro-mechanical oscillator which can be put in an entangled quantum state with a qubit. See What exactly does Aaron D. O'Connell's experiment show?, for a basic theoretical overview.
When the qubit and oscillator is in a coherent superposition of direct product states, we make an attempt to view the oscillator, which has dimensions only in the micrometer range, using a magnifying glass of high resolution, what do we see(or, if a similar operation has already been done, what was seen)? I know that for viewing the micro mechanical-oscillator using an optical device, we are required to irradiate the oscillator with visible radiation. But, I am not sure if that's always strong enough to break the coherence.
This question also assumes the oscillator to be in the same state as that of the previous question. Consider a small massive bob, which is set up such that, any tiny changes in the gravitational field in it's immediate surrounding could be detected. It is assumed to be placed close to the micro-mechanical oscillator. Let this bob also be kept in an ultra-cold environment as the oscillator, so that one need not worry about environmental decoherence. In this context, we expect there to be a minuscule variation in the gravitational field experienced by the bob due to the varying distance between the bob and the center of mass of the oscillator. What does our measured value of gravitational field due to the oscillator look like as a function of time. Is it a smooth sine function?
Since these questions are experimental in nature, answers that are based on information about similar ideas that have been implemented in experiments of the past are appreciated more than speculations.
Note: In the first question, I am using the word 'see', as it's always in principle possible to observe a micro-meter sized object using an appropriate optical lens. To be more precise, let us say that we wish to see a tiny marking on the oscillator.