ほんとにこう言われたのでびっくりです(笑)
多分光の散乱の仕方とか強さとかで区別つけるんだと思いますけどねー。
説明を端折られた印象がプンプンしますが、まあしかたないかなと。
明日はもっとわけがわからなくなるよ！(笑)

They really did tell me this, so I was shocked. :-) I figure they could differentiate by the strength of the light or the way it scatters or similar, though. I was put out by having the explanation cut short on me, but hey, what are you going to do?

Tomorrow, things become more incomprehensible! :-)