I had the problem with a Honda back in the 80's or early 90's. It used to happen over a certain mph range...I don't remember just range that was...but I'll take a guess and say it was between 50 and 60 mph. I had 2 choices; speed up or slow down. When it first started happening, I would stop and look for a problem. I never did find out what caused the problem since I sold it to a police officer that lived in my neighborhood. On my 09 SEUC, I start to feel it coming on around 115mph and that's when I back off. Smooth until I get to that point. My 06 VRSCSE2 doesn't seem to have any problems at any speed thus far, but I've only been into the low end of the 120's with it so far. All of the above is going in a straight line.
The only other experience I've had with the wobble was on my 07 Road King Classic going through sweeping curves and I would always have to slow myself down because I felt like I was losing control in curves on that bike all the time.
Yes, I feel bad for this guy, but it makes absolutely no sense for someone to experience this for the first time and speed up. Seriously, if you start having a wobble that bad that you are going to lose control, who speeds up? I wouldn't just slow down, I would stop and check the bike over to make sure something isn't drastically wrong. Last year when my front end started feeling strange at 95mph, I pulled off the road immediately. I was almost down to riding on the rim. Anyway, the point is, I certainly wouldn't have speeded up.