Weelllllll... There's a school of thought that says line-shy is a myth and then there are those who have seen it in play. Personally, I believe highly pressured bass associate pain, disruption, confusion, etc. with human activity. In a heavy cover environment such as a laydown, weeds or pads, the line size is probably not that important. The line pretty much blends with the living environment the bass are in. In a clear water/open water scenario, the line becomes a distraction and can spook the bass. I never believed any of that stuff until I started fishing clear water reservoirs. The usual 10#-12# line caught bass, but (at the suggestion of a friend), when I switched to 6# or even 4# the bites increased a lot. Was the lighter line causing a different lure action? Don't know. But, the strikes increased and more bass made it to the livewell. Bass are curious creatures and much more complicated than that tiny brain would suggest, imho. Lol!