Or some will lie and say they are authorized when they aren't, like TheZeb used to do. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gifUsually it's not an issue of buying online vs. offline, it depends if that retailer is authorized by the manufacturer. If they are an authorized retailer, you will get a full warranty, otherwise, no. Generally if they are authorized they will say so, and the price will be a bit higher. I have bought equipment from eBay before, and so far, have been okay.
I know JL doesn't honor the warranty from any online purchases... not sure about who else does the same. Arc, but they're not sold at Woofersetc.