I can't say for sure. I was on a long trip into Washington and Oregon. At some point the ABS light came on and the bike seemed to lurch a bit. I pulled over cycled the ignition and all was good again. The ABS even worked as I tested it in the gravel. I started to hear some squeaking that didn't seem to correspond to braking or bumps and had a small independent shop take a look. He pulled the front calipers (I thought a pebble might be causing the squeak) and found nothing. He also took a look at the rear and couldn't find anything obvious. A day later, I realized that the ABS ring had spun 90 degrees clockwise and was rested against the brake arm. ABS still worked fine and nothing was making noise or out of the ordinary. Once home, I found a new ABS ring on line (the original had broken guides/nibs that hold the ring in place)and when I started to take it all apart the axle on the pumpkin side could be spun after I took the nut off but the hex side was as tight as could be. There was no way to remove the axle from either side so I had to saw the axle in half on the brake side and pull the pumpkin along with the wheel. Once it was off, I had a mechanic friend press it out as best he could. The hub stayed on the axle, the ABS ring broke and the other half of the axle had the bearing spacer basically welded on. I have some pictures but don't know how to get them on here.
So, the ABS light happened around 2500 kms into a 5000 km trip.... no idea when it broke but it was moving enough that it ground the square edges off of the wheel on the pumpkin side where the hub sits against the wheel (hence the need for a new wheel) and the hub was rolling unevenly as well based on the wear that was on it.
FJRGuy was gracious enough to offer me the use of a spare 2007 wheel he has but it turns out they are different. The 2007 has a gear on it where the 2009 has the ABS sensor ring. We found that out the hard way....