I’ll be honest, I wouldn’t be the one reporting a church for staying open during COVID shutdown as long sa people were social distancing, hand sanitizing, and, from the time it was required in US, wearing masks.
(We were told by our government durig the first month of our shutdown last March to NOT wear masks because the government authorities said that actually increased our risk. Instead we were told to just social distance, not go out unless absolutely necessary, and not touch our faces. The governor here didn’t mandate masks till late April.)
I was personally aware of one church that continued holding public Mass daily for about a week into the shutdown, with about 5 people at each Mass all widely distanced and using hand sanitizer, until the Archbishop got wind that a few churches were doing that and made them all stop. I was not the one who told on them. I also saw another church (about 30 miles away in same Archdiocese) on video that seemed to have a significant number of people going to daily Communion until the priest figured out he shouldn’t be streaming that and had them turn the camera away when it was Communion time.
Now, if some church were packing in the bodies, not social distancing, and no one was in a mask, I might have become alarmed and contacted the pastor and/or the bishop. But I’m not sure. I might have just let it go by. I might have joined the gathering if the church was close and not in the heart of the urban COVID area. I do not know, because I wasn’t in the situation.