Doesn't this experiment have a simple explanation that measuring something is essentially entangling yourself with it? So at the end of the thought experiment, both scientists and the test device are in a superposition together...

...except it's not that simple, and here is why I don't like those experiments (and why in reality, they're always realized using atoms, and not cats): there's no Wigner, or Schrödinger's cat, as a unit in physical sense. They're made of atoms. Atoms that interact and radiate information all the time. That box with a cat with it, the cat radiates information at the speed of light, which gets absorbed by the box and reradiated away. If the result of your thought experiment could be changed or confused by the following setup:

- a) put a broad-spectrum camera suite around the box prior to the experiment

- b) have it record data on the hard drive

- c) have the experimenter do their experiment

- d) have someone pull the data from the hard drive and read out the actual state of the experiment subject

... then it means your explanation for the thought experiment is wrong.