Does the previous post come in something approaching English?
I'm guessing you are someone who just buys someone else's handiwork - this will certainly force other methods to be devised, simple MAC cloning won't work and MAC 'scanners' don't get past it.
50Mbit should be considerably harder fortunately and well, well beyond the capacity of the average ebay buying idiot, and the people who confuse signed DOCSIS config files with MAC addresses
Virgin Media finally catching up with most other cable companies in having something approaching security.