The beta test site should be separate from the development machines. It should be a replica of the real site in every sense (though perhaps scaled down — e.g., if the live site is 10 load-balanced machines, the beta test site might only have 2), so that all the different ways that networked computers can interfere with each other can have full rein. It should be set up by the sys admins but tested by a very special sort of person: not a programmer, but someone who understands both computing and end users. Like a test pilot, she should be capable of making the crassest mistakes while noting exactly what she did and what happened next.