Hmm. I'm trained in physics, too, to some degree, but I stopped at a bachelor's degree.

What, in your usage, is the difference between "unlikely" and "may be"?

(By the way, I'm not arguing against "unlikely" wrt any of these things...)

"may be" doesn't give you an idea if it's 50% or 1% or 0.0001% likely. "Unlikely" does give you an idea: the probability is small.

When you're talking about an extraordinary claim, it's a good idea to use "unlikely" and not "may be". The moon "may be" has deposits of green cheese, we just haven't found them yet. It is unlikely that the moon has deposits of green cheese. It is likely that the EM Drive thrust measurement is measurement error.