User blog comment:Shacho/Adventure Map HELP!/@comment-4445052-20120609025432/@comment-4445052-20120614230258

It's impossible to modify Spawners without the GUI, and you need SinglePlayerCommands to get things required in the map or whatnot unless you want to make it all legit. Meaning you can't use Spawners. Plus you'll has creepers. Meaning your screwed anyway cause they might spawn.