[dave9000]

For the accelerometers the problem was the tiny tilting of the sensitive axis in the gravity field. In this case you're probably right that this doesn't matter - but in general it is difficult to rule out every second-order effect when the forces at play are so small with respect to g.

[lisper]

OK, that I guess that kinda-sorta makes sense if the accelerometers were rigidly mounted to the floor. Was that the case? Because if so then what you would have would basically be a seismometer, and floor bending from the test masses would, it seems to me, be the least of your worries.

[dave9000]

Yes, the accelerometers were mounted on an optical bench and of course we could detect any minor earthquake (sensitivity was around 1e-10 ms^-2). The bending of the floor due to the presence of people in the room was noticeble indeed.

[lisper]

That makes sense. Thanks!