Does this happen at other parishes?
I took one of my teens to confession at another parish, since we know our priest fairly well, and he wanted to be anonymous. The church was small, and I sat down in the back to wait for him. I could CLEARLY hear the priest saying the words of absolution from my spot in the back. Who knows what the two women in the front pews - feet from the confessional - heard! Why do people(who are clearly not waiting for confession) sit so close to the confessional? It was 45 minutes before Mass, there were tons of other seats available.
I used to see this at my own parish. A half dozen people - none waiting for confession - sitting in close proximity to the confessional nearly an hour before Mass. They are no longer there. I asked my priest once if he said something to them, but he denied it. I do know that when he is in the confessional, he kicks on the A/C fans which are located above the confessional and provide a good grade of white noise that pretty effectively drowns out the conversation from inside.