I just had an interesting experience, where a customer got a malware infection, and shortly before I arrive, their ISP decides to block their internet access.
So I get myself set up, to remove the infection via UBCD4win, and I cannot get spyware signature updates.
So I found myself in the situation where I couldn’t fix the problem without taking the computer back to the office (where I had a working internet connection), in order to remove a malware infection!
But then again, it shouldn’t be a big surprise… the internet is the main vehicle for spreading malware in the first place, so it follows that you need the same internet access to disinfect a PC.