Hello Eugene,
Sorry for the delay, I've figured this out now.
AdGroup.Settings.ExplorerAutoOptimizerSetting has the following effect:
optIn == true -> Enables Aggressive Targeting ("Aggressive targeting" and "Let AdWords automatically find new customers" are checked in the UI),
optIn == false -> Disables ExplorerAutoOptimizer ("Let AdWords automatically find new customers" is unchecked).
There is no API field for the Conservative setting at the moment, I'll log a request to include it in the future API versions.
-Danial, AdWords API Team.
On Friday, July 25, 2014 4:57:26 PM UTC+4, Danial Klimkin wrote: