I’m really curious about that aspect. I wonder how many casual fans will not care if they do use the effects should they go that way. By covering the seating area, you’ve taken away a visual reminder of the missing audience. No, it won’t be the same as shows with few audience shots. No question. But it’s possible to over analyze when looking through the lens of someone with more invested in the show than someone just looking to be entertained with some light fluff for a bit of the day.
Even as a closer observer, and even if I might roll my eyes at sound from a crowd that doesn’t exist, it would not give me a moment’s hesitation. And after a show or two, I just wouldn’t care. If that provides a sense of normalcy, albeit artificial, fine. It is a TV show. Nothing more or less. Laugh tracks didn’t bother me even when I knew there was no audience. This is no different in the grand scheme of things.