May not sound like a great idea at first, but I think you'll find it won't hurt a thing. So I would have to agree with the dealer. It may not break in as quickly, but it will break in. As far as being smokey, nope! Not even a light haze. As far as any other issues running 50:1, nope!
50:1 actually makes awesome fuel stabilizer for 4 strokes. I use it frequently on engines that are going to be sitting around for a while (including my lawn equipment and pressure sprayers). There's nothing else that will stabilize the fuel while giving the valves, rings and cylinder bore a nice thin protective layer of high quality oil.
Not my trick. It was passed on by a a Florida outboard tech that's been working on boats forever (one of the very few I trust). He said he started using it on inboards and I/O's, but when the 4 stroke outboards came out, he started using it on those as well....
The ONLY caution I would be aware of is an engine with an oxygen sensor. They may not like that oil at all. I don't know that for a fact, but would hate to recommend it and have it cost somebody a sensor.... -Al