Are these even amplified antennas? I'll bet what we're talking about here are those silly pieces of plastic with that super-duper-ultra-scientific foil pattern printed on them, you know, the commercials where people would stick the "antenna booster" BEHIND THE BATTERY, then put the battery back in, and HOLY COW I'VE GOT FIVE BARS NOW! Worse than snake oil... Ranks right up there with muffler bearings, and turn signal fluid.
So, now all the idiots who got roped into pyramid sales schemes to resell these pieces of useless film are trying to recoup their losses by saying these work "just as well" for AM, FM and TV?!? Hah! All the more power to 'em!