P2P ISP Moaning
1) I *PAY* the ISP for a connection, this connection has a limit if *I* go over the limit I pay more. This basically means that if an ISP says I only have a 1 GB limit then what I choice to do with that 1GB is entirely up to me.
2) If the ISP can't cope with the bandwidth they have three options reduce the bandwidth limit, upgrade there network or change there pricing (up or down) anything else is an excuse.
3) Any P2P traffic that is confined to there IP block is cheaper for the ISP as it doesn't transit across there external links (unless there routing is wrong), this makes local caches/proxies an attractive solution but can be a legal gray area (thanks to our mostly dumb laws put in place to protect business and not customers).
4) The whole industry (ISP) is basically trying to get profit out of existing copper networks (with the old BT fibre network in places), this is never going to work in the 21st century as bandwidth requirements are only going to go up i.e. HD content.
If I was getting my internet connection for free then I would agree that they might complain about other companies using there network, as I *PAY* them to use there network with a limit I can't see how any of them can complain.