I do it all the time, and when I do, I strictly use hand signals when it comes to change lanes. When I use my Throttlemeister, it allows me to rest my throttle hand.
However, as you mentioned, you better have the capablity to swerve with one hand if you need to. Just the other day on my way to LA, cruising about 80mph indicated, and riding with one hand, some woman from my right made a bad lane change on me as I was passing her. I swerved to my left keeping a steady throttle, then I put my other hand on the handbars and hit my horn. Once I applied my 130 decibel Stebel, she quickly went back where she belonged. I tried kicking her door at the sametime but I missed, I swerved too hard dang it.