After all, they've made the same claim repeatedly for 15 years after their first experiments were demonstrably not what they claimed.
Let the experiments decide what is right or wrong.
Low earth orbit isn't perfect either. You still have micro gravity. And the experiment requires a lot of power, and very sensitive instruments to measure the phenomenon. How do you get sensitive instruments which are expected to be operating near their error threshold into orbit without damaging them?
Orbital experiments will have to be smaller, and use less power, so the effects will even be smaller. But the instruments will have to be tough enough to withstand 5G. And the apparatus could still be introducing other errors, like coolant momentum, which also isn't magically eliminated by being in space.
You put the engine in space, with solar panels, and you see if it stays there or falls back to earth.
There is no experimental error, or even measurement devices.
It is a space engine. Either it flys or it doesn't.
Over the course of a year, it will be obvious if it works or not. Because if it doesn't work it will fall to earth.
Not just repeatable, but in different physical configurations of the drive test bed. Right now the tests are using a rotating base that has little to no calibration, much less the hardware, if I understood the link correctly.
We have a thing, it's owner claims it works by either Method_A or Method_B, science is about taking the thing, testing the crap out of it, and being able to say at the end of all if it, "actually it turns out it works by Method_C"
It seems you have some wires crossed somewhere. Science and Rational behaviour are unrelated, they are quite well correlated but as separate concepts they are not causally linked. Historically connected obviously, but not causally linked.
Extraordinary claims require extraordinary evidence, which is why every good scientist expects this effect to go away (regardless of hope as to whether it is a real effect or not).