It's a matter of fact that every vendor of telco equipment has to provide a lawful-interception interface when doing business at a serious scale (say, enabling services for >10k end-users). That holds true in countries with questionable political systems, but even more so in Central/Western Europe and especially in the US. It's really just how the technology is handled and used. Regarding conspiracy theories: there's…
We at Sipwise implement VoIP switches at major ISPs in Europe, and the most uncomfortable question, which is ALWAYS asked (mostly just as a side-question, like "Btw, I suppose you support it anyways, so how does your solution work in that regards?") is the one of lawful interception.
There's a specification defined by the PacketCable consortium (http://www.cablelabs.com/packetcable/downloads/specs/PKT-SP-...), and I'd say that almost every major vendor has implemented it in one way or the other in order to be deployed at cable ISPs.