Gatekeeper won't actually let you open an application from a developer that it hasn’t already approved - you'll know when it does as the message 'X program can't be opened because it is from an unidentified developer.', it's somewhat limiting but gets the job done, most of the time.
The company has a strict software policy and actually prevents the download of dangerous software in many instances via a feature named Gatekeeper. Apple has a great reputation for keeping their devices free from the scourge of malware attacks and viruses.
