100 µN is tiny.

How tiny?

Ultra-miniature force plate for measuring triaxial forces in the micronewton range (7 page .pdf)

See figure 6. A running wood ant generates ~ 100 µN when its leg hits the surface.

They're claiming to see 100 µN when running a lot of current and RF power in a gizmo.

Yes, they're trying to eliminate any sources of error.

And of course, any non-zero result from this EM Drive experiment is interesting, but as you say, it seems very unlikely that they're seeing any new physics here. They're likely still seeing spurious forces.

My $0.02.

Cheers,
Scott.