Putting yourself or a member of your team inside the target organization during a penetration test can be an expeditious way to access the data network infrastructure from behind the border controls. It is usually very easy to accomplish your objective from inside the building than from outside.
Physically penetrating your target company for the goals of collecting sensitive data might not seem immediately clear. Actually, physical access is increasingly a common factor in cybercrime, particularly in the theft of personal private data for the purposes of identity theft.
Breaching the border controls of any company will vary in difficulty depending on the sophistication of the systems and procedures the company has employed to stop such breaches. Even if complex systems such as biometric locks are employed, they usually are quickly bypassed because of relaxed or badly followed procedures.
In contrast, an open environment can be quite hard to breach if employees of the target company are fully trained and follow appropriate procedures. Gray hat hacker must make an accurate evaluation of the environment before trying a physical penetration. If the attempt is noticed, the whole penetration test may be compromised because the workers of the target company will talk about a tried break-in!