I don't really know enough about this to comment.
Well, imagine an ohmmeter, for example. According to my Experimental Physics teacher, it measures the current when the voltage it generates is applied to a material, then calculates the resistance. If you attach this to a superconductor, you have current passing through a superconductor; current that's not supposed to be there. Now a voltmeter. This one doesn't really do much in terms of changing the circuit, since its resistance is about 10*10^6 Ohm, while the resistance of a superconductor is zero (or, at least, very, very, very close to zero). Ammeter. This needs to be connected in series (I don't know the proper term for this, so forgive me if it's not accurate), and, while their resistance is small when used in a common setting, it's still very high compared to that of a superconductor (10 Ohm>>0 Ohm).
These are just the three most common devices used. Now consider the fact that the superconductor will be used to minimize power consumption. That is, it will be used as we use wires. An ohmmeter can't work like that. It will break down. And an ammeter, if the current is strong enough, which it must be for this kind of experiment, will fry (inside; the exterior will remain the same, but the fuse will melt and the device will become useless when used in a certain scale).