I heard a woman who is a native English speaker saying "someone will say something like that in public or under the glass." I've not heard of the idiom, "under the glass", but considering the context it seems to mean something opposite of "in public". Or, I just might have heard wrong. Could you kindly tell me what this exactly means or whether it is misheard and there would be another proper words?
＊Please allow me to explain about the context behind the conversation. We had a discussion over the case where certain people said very discriminative words to some minority group. I said some anti discrimination laws could be deterrent for those cases.Then she said, like "Even if we try to pass such laws, people will still say something like that to you in public or under the glass."