That is an expensive and slow way. The more prevelant and exploitive way of using the AI is against indeps (for early expansion). Their Archers/xbows/missile units are all set to fire closest. Thus you can leave a single unit with a shield in front of a mass line of archers. Most of the time if you have a decent archer brigade, the lone shield bearing lamb will surive due to the spread of arrowfire, while you incure no losses and most indeps break before they get to your line.

Another is that all normal fighting troops are on attack closest (as far as I can tell, I've never had anyone attack a flank that didn't engage them first). So you can exploit it in that fashion with spells, retreating options, etc.

Side Note: Nearly all Indeps (with the exception of some Amber Tritons, Amazonians) have only normal priests for their morale support. So you can easily use fear to cause routs without worrying about any losses.