It does add more lines yes.  However, there are two reasons I do it.  First, it just makes it perfectly clear on a quick skim of the code that a line is nested.  Second, and probably more important, merging goes a lot smoother with the nesting.  I've shot myself in the foot with merging because the tool couldn't see the differences with the single line versus the nested approach.

Having a couple of extra lines because of braces never hurt anyone :) Of course, you can write some nasty code because of too many levels of nesting in a method, but that's a different story.