What of cases like non-Catholic receiving the Eucharist. I knew a Lutheran professor and at a Mass on campus, I saw him take the Eucharist once. Later in class I talked to him about it and told him politely that it’s actually not allowed, but he tried to justify that he can because he does believe it is the Body of Christ.
I also read about tourists from non-Western countries like Japan who go to the Vatican, attend a Mass and don’t even understand what the Eucharist is, but just follow the herd and go to receive.
A worse time I saw was giving it to the corpse of a relative of mine who just died. They somehow managed to get a priest to give the dying man hosts to keep in a pyx which he carried around (which is against Canon Law). After he expired, his wife suggested putting the Eucharist in his mouth. I said, in polite and gentle terms, that you can’t do that (and I know what I’m talking about – you REALLY can’t do that). I left the hospital room to help them with the funeral arrangements. When I returned, I discovered that they did it anyway, I’m pretty sure it was intentionally while I was gone.
That was his third wife, with whom he only has a civil marriage. While we could theoretically say that he might have gotten absolution for that and can receive the Eucharist, we absolutely cannot say that they can give the Eucharist to a corpse or even that they can let someone carry the Eucharist around.
With both the professor and my relative, I did say something. But with both cases, I was ignored.
One time at a weekday Mass, a woman apparently tried to pocket the Eucharist. A sister noticed and in a slightly aggressive way signaled to another sister to do something about it. It made the woman cry and the second sister comforted her. I noticed the ruckus from my seat. I think those sisters did the right thing.
Problem is though, for people like you (the original poster) and myself, we’re laypeople and we’d be ignored. At least those sisters came from a position of authority, and I don’t want to have to flash my Religious Studies degree just so people would believe me.