You're not understanding. Even a perfectly-designed filter still has harmonics. That's why my filter which was supposed to cut-off at channel 15, still allowed me to see channels 39,40,41 - the harmonics snuck through as a blurred but watchable image.
And no it isn't stealing when the cable company does not do its job properly. I asked them for locals only - they gave me locals plus channels 39-41. The blame goes on THEM not the customer, and the government would fine Comcast for incompetance, not the customer. (Actually Comcast would probably just bribe the local politicians and clear themselves of all charges.)
And as for theft - the government/companies steal from us plenty. I consider the ~2000 billion bailouts of the past year to be theft by the corporations from the taxpayers. Rob from the poor; give to the rich; that's basically what happened.
My Free TV streams 19 Mb/s == 6000 GB/month per channel. No cellphone can do that. WHY kill off this excellent service??