So yes, kT is small on average (does fluctuate) and it is also 1 kT per degree of freedom. So yes, in principle a few hundreds of atoms could randomly fluctuate

So yes, kT is small on average (does fluctuate) and it is also 1 kT per degree of freedom. So yes, in principle a few hundreds of atoms could randomly fluctuate in energy to create this effect. However, this is hyper unlikely. I would be suprisd if it happened once in the life time of the universe. Also consider that you cannot create Maxwell demons[1]. [1] https://en.m.wikipedia.org/wiki/Maxwell%27s_demon https://en.m.wikipedia.org/wiki/Maxwell%27s_demon