A good friend of mine was told the exact same thing by our dealer. Naturally the engine ultimately failed (not SERT related). When "Tech Services" was contacted for warranty authorization, my friend was told his warranty was VOID because he had a race tuner on it. When Tech Services was informed that the dealer put it on the bike and said it would not affect his warranty, Tech Services said "it doesn't matter what the dealer said, the customer is ultimately responsible regardless". Needless to say, he had to pay for the repair ($1200) and an extra $150 to reinstall the factory map to reinstate his warranty.
I know others of you have had better luck with Tech Services, but with a SERT we're playing roulette. He might have an action against our dealer, but Harley says their not liable. Harley will look for and use ANY excuse to void a warranty if they possibly can.
Harley can say anything they want, and as we all know they spout BS on a daily basis. Did your friend enlist the aid of an attorney familiar with warranty law? If he had, I believe you would have seen tech services back off real quick. The laws are there exactly because of chit like this, but consumers still have to be informed and willing to fight for their rights.
BTW, don't you find it a little strange that a dealer modification results in a blanket voiding of the warranty, but if you pay them to reinstall the original calibration your warranty magically resumes as if nothing happened? What about all that damage to other parts that obviously occurred due to that illegal modification but didn't show up yet? You know, all that extra power

that has brought the clutch and trans to the ragged edge of failure. Are they going to go back and cite the past modification, documented on the engine repair order, to once again jerk him around?
To paraphrase Hoist, FTW and FHD.
Jerry