Considering the impact of physical obstructions such as cubical walls and glass partitions is crucial in a site survey because such structures can attenuate the Wi-Fi signal, leading to potential coverage issues. By evaluating how these physical elements affect signal strength, the technician can position the access points in locations that minimize signal blockage or reflection, providing uniform coverage across the office. The correct answer focuses on physical obstructions because these are often overlooked when assessing problems related to wireless signal strength. Other answers, such as the encryption protocol mismatch or updating firmware, are important considerations for network security and device performance but do not directly address the survey goal of overcoming physical barriers to ensure signal coverage.