We do one-lane in all the leagues I bowl on. One is a mixed, fun league with mostly non-serious bowlers. We never have a problem with non-serious people not understanding lane courtesy. We do bowl next to a college league and have had some problems with it but it doesn't take too long to educate them.
The other league is a mens' league that's about as serious as leagues get around here (which isn't that serious). Again, no problems with lane courtesy.
We do give plenty of leeway for splits (and the rare honor score). There's no sense in bowling next to one (or two!), you're more likely to get one yourself or leave something on a good shot. Big-Four to the left, 7-10 to the right? I don't need that kind of mojo working against me. My teammate doesn't even let the ball "see" the splits, she covers it with a towel until it's gone.
SH