Lie Detector Test

That's not how the lie detector works. They don't ban.
You can't even target someone with a lie detector unless they're actively attacking or you still get the "target must be attacking" message, so if she was picking up drops at the time there is absolutely no way this was the lie detector.

She was playing in the Ghostship, wasn't standing in one spot too long while attacking, and was picking up her drops.

That's the exact quote from this guy. It appears as though he was describing in general, not at the moment she was banned. From agony's post, I can reasonably infer that he was nowhere near when the banning happened.

If we assume that, then it's possible someone used the lie detector while the character was attacking. If so, then IDK, maybe autoban kicked in? We all know how faulty the autoban system is.