The Gemara says already that we don’t have Kavana and the Halacha exists nevertheless. But, I have heard numerous Heteirim through the years. There are stories of Gedolim who stayed out of Shul until everyone finished.
There are a few things involved here. Walking in front is Assur because of Kavana. Passing through or sitting, for a non-Mitzva is a problem all around because of the presence of the Shechina. Perhaps the less Kavana someone has, the less you have have to worry about the first part but the second, albeit less Chamur, problem still exists.
There is a concept in other areas of Halacha that you can’t Assur someone else’s property. I’ve heard this applied to our topic, too. In the isles and even near other places, when the person is sort of stepping into others’ territory, he is giving up or can’t Assur his 4 Ammos.
We can always see Medakdekim being careful about this, but it’s hard to give numbers because most people stay by their place throughout the Tefilla.