A telescope would do little to discern if it's an actual satellite or a stratellite.
Aside from previous comments pointing out the fact that a telescope should be able to see the fact that the stratellite is supported by a balloon, let's assume for a second that it IS somehow a balloon despite being shaped exactly like the constantly changing space station. ISS is a very fast moving object in the sky when it's straight over your head. It moves about 1.5 degrees per second at the peak of its pass. Assuming it were really 300 kilometers away as described by NASA, then that correlates to about 8 kilometers per second - orbital velocity. Assuming, however, that it is actually a tiny balloon only 20 kilometers straight up (as that would be the height of a stratellite), then that 1.5 degree per second motion (which you can easily measure for yourself with a telescope) still correlates to a velocity of 1,919 km/hr. How is an unaerodynamic structure like the ISS able to fly at that high a velocity without being ripped to shreds by extreme aerodynamic forces (20km is still easily low enough in the atmosphere to experience extreme atmospheric heating)? How is it able to maintain that velocity with no sign of any engine emissions whatsoever? And best of all, how is it able to show up at exactly the right time and place as predicted by its supposed orbital elements? Even if someone wanted to fake it by using a stratellite drone shaped like a space station, figured out a way to magically keep it intact, and figured out a way to get it going fast enough with no sign of engine emissions, any given flight path it could take would only produce a path that would match predictions based on the published ISS orbit for one very specific location. Anyone else nearby looking up would see the "stratellite ISS" appear in totally the wrong place, and others farther away wouldn't see it at all. The fakers would have to magically know ahead of time who was going to be trying to observe the ISS, as well as where and when exactly they would be observing it. If two observers planned to look for it during the same predicted pass from locations separated by a few miles there'd be no way to adequately fake it for both observers simultaneously. Therefore, it is impossible to adequately fake the ISS and shuttle using "stratellites," even for naked eye observers.