Well Ensemble said in an interview that you will not lose games simply because you forgot to rebuild your military. This obviously means that you can replace your losses very fast. But is the general build time of units extremely low? If that was the case some kind of restriction, civs with early economic advantages would simply be too strong.
My guess is that the units you build will actually be recruits that come from your home city. New recruits will fill up at your home city over time. That means you cannot crank out too many units early even though you have the resources since you do not have enough recruits. Later on you will have more recruits, especially if you forgot to make military for a few minutes.
Ensemble could of course have a completely different solution. But having recruits gradually spawn in your home city (and maybe spawn faster as you advance in ages)and having really low unit build times would make it easy to replace losses without making rushes too strong.
[This message has been edited by MockHamill (edited 02-26-2005 @ 03:09 PM).]