From the description of how the Steam client will behave on someone's PC, I'd say this is the best of a "not so happy - not so happy" solution for Developers and End Consumers alike.

It doesn't invade your machine, it sits in the task bar if you let it (you can tell it not to fire up at start up) and if you don't want it there you can exit it from your processes and play E:TW off line.

You can then fire it up every now and then when you come onto the Orgh and see there is a new update to be down loaded.

It will then do it's update thing, you will then say things like 'oooh' and 'haaaa' as the new patch from CA fixed a few bugs and balancing issues.

You can then turn it off and play E:TW to your hearts content.

Me likey likey!!