I expect that Sky broadcast multiple copies of the sports channels simultaneously (at a minimum, one with and one without the pint glass logo). Home subscribers are set up to tune[1] to the channel without the logo, the more expensive pub subscribers get the version with the pint glass logo.
If a pub landlord subscribes at home, and then take their receiver/smartcard to the pub and plug it in there, the receiver will still display the home version of the channel without the logo. That's what the inspectors are looking for.
(Alternatively, the smartcards used for pub subscription could insert the image into the decoded stream, but I'm not sure if they have enough processing power for that. The end result would be the same, though -- no expensive subscription, no logo.)
[1] Yes, it's a digital system with multiple program streams per frequency, so 'tune' isn't quite the right word, but it's close enough.
> the receiver will still display the home version of the channel without the logo. That's what the inspectors are looking for.
But why can't the inspector just look for: is this pub showing the channel, and is it in our database of pubs which are allowed to show the channel? That was what I took from scrollaway's post, though I might have misinterpreted ver.
A for some reason I thought you were talking about a COTS receiver and just pirating the business channel completely, not using an actual home receiver.
I think there's probably a perception issue at play too. Buying a pirate decoder card from a shady dealer is 'obviously' wrong, while using a subscription that you've already paid for in a different location is a different matter. I could see pub landlords being more comfortable doing the latter than the former.
I don't know what the current state of the art for pirate decoders is, but if it still depends on extracting a keystream from a legitimate decoder in real time and sending it to the pirate receivers, limiting the number of legitimate receivers of the business channel to would also help cut down on piracy of the business channels by reducing the possible sources of key material. The high cost of a subscription and limiting subscribers to pub businesses only also reduces the number of potential key sources.
The current state of the art prevents this technique from working on Sky's highest value HD channels. (HD channels require a newer set top box with a later generation of decryption abilities, and these ensure that any liftable keystream is specific to that one receiver, so it has no value if distributed, and no ability to activate other receivers.)
