Different kind of biker this time. In 25 years of riding, I’ve never heard of an “EPA sticker”, and I’m quite certain that no bike I have ever owned had such a sticker (and they all had stock or extremely quiet aftermarket pipes).
But then again, its chuckleheads like this who make stupid laws possible:
[Biker] Bill Ferraro, president of the Union Ironworkers Motorcycle Club, Local 580, testified that “it’s unsafe for us to ride when the pipes are too low [i.e., quiet].”
If you want to be safer, take a rider safety course and wear a real helmet. (Which isn’t to say that straight pipes don’t sound incredibly cool; they do, just in a really annoying-to-the-rest-of-the-world kind of way.)