Laptops have become an indispensable asset in today's digital age. They often contain highly sensitive information, such as credentials and confidential documents. As a result, the value of a laptop is an accumulation of the value of both the physical device itself and the cyber assets it contains, making it a lucrative target for theft. Educational institutions have a large population of potential victims of laptop theft. To mitigate this risk, we investigate whether a simple warning sign can reduce the opportunity for potential offenders. To this end, we have conducted an empirical study to observe the prevalence of students/staff leaving their laptops unattended at a university study hall at the Delft University of Technology in the Netherlands, both with and without a warning sign. We observed 148 out of 220 subjects leaving their laptops unattended in just three weeks. The results also showed that without the warning banner, 75.5% (83 out of 110) of subjects left their laptops unattended and with the warning, only 59.1% (65 out of 110) of subjects showed the same behavior, which is a significant reduction of 16.4%. In addition, a qualitative analysis was performed on the responses of subjects who left their laptops unattended after the warning banner was placed. The results showed a mix of convenience, and a blind trust on the safety of the faculty. In conclusion, a simple banner was effective in reducing the opportunity for laptop theft. However, the percentage of laptops left unattended was still high even after the introduction of the banner.