That’s the very reason why it’s actually
better for an ordinary member of the congregation to do this, rather than **a communion minister having to interrupt his sacred duty to chase after someone walking away with the Body of Christ **in his hand/pocket.
The appearance of authority is conveyed by manner and tone of voice. Someone abusing the sacrament is probably not a regular parishioner and would have no idea who the liturgy committee members are. Anyway the purpose of a liturgical committee is to contribute to discusision of how to make the parish’s liturgies effective and appropriate. Joing a liturgy committee does not make one a “super-Catholic” who has some special authority over others than ordinary Catholics do not have. We all have a duty to protect the Blessed sacrament if the occassion arises. No that does not mean constantly spying on others suspecting them of trying to abuse the Eucharist, but if you see it happen right in front of you,
then for God’s sake (literally) do something, don’t just sit there hoping “someone in authority” will do something or that you’ll tell someone afterwards. Quite possibly you were the only person who saw what happened and who knows it was an abuse of the sacrament.
God’s sake=God’s benefit?

Well done. I only wish this was done in my parish. Nobody at our parish church is
ever reminded that Communion is just for Catholics (who have fasted and are in the state of grace and who wish to receive it and have not received at an earlier Mass that day).