It's definitely quite nice being able to code while mobile. I've often used a laptop while travelling, and internet connectivity can be something you get used to not having.
Sure, if I'm stuck with a particular error message, a google search is often the quickest way to resolve. And yes, if you have to add a library that you don't currently have, you're out of luck until next time you're connected.
But I've definitely found some of my most productive time while disconnected.
I've found it depends on what type of coding I'm doing. Working on an Objective-C in Xcode? I most likely have everything I need. Working on the first stages of a Rails app? Dead in the water at the first sign of `bundle install`.
Sure, if I'm stuck with a particular error message, a google search is often the quickest way to resolve. And yes, if you have to add a library that you don't currently have, you're out of luck until next time you're connected. But I've definitely found some of my most productive time while disconnected.