EWS failure two times, seven months apart. No parts replaced first time, due to not being in the affected VIN. Dealer said the antenna ring did not cure the problem. I think since they did not have my extra key they really could not test the new ring. See below for why.
The second time the ring really did fail. I tried maybe 50 times to get it to work. It finally worked on the 51 time, and i got home ok. Luckily I opened the fuel cap just in case the key worked. I immediately shut the bike off and back on when I got home and it showed EWS again.
I asked the dealer for a new ring before I moved the bike out of my garage. Thankfully he obliged, so I got to mess around with the old and new rings.
First I found the key had to be inside the ring for positive recognition. Hence you almost have to have a second key to use a spare ring. Some people have said you can just hold it next to the key in the ignition switch. I found that to not be true.
Second when I was stranded, I tried 25 plus times, then had lunch, tried 4 or 5 times, had beer, tried 25 more times, no joy... I gave up called AAA, had beer, tried 3 or 4 times, IT WORKED!!!! After I was home, the ring started recognizing the key approximately 50% of the time.
The bike had about 1500 miles on it the first time, and 5000 miles the second time.
Probably the most information on EWS is found at ADVrider.com here: http://www.advrider.com/forums/showthread.php?t=245456
Information is a good thing. I have found this forum to be very accurate with potential problems. I have the clutch noise problem and brake pad light too, but I'm not worried because i know you all are keeping us in the know.