In many surveillance systems, an operator will have to make a decision on whether a target is present or not from the outputs of a sensor. Here, we assume that such an operator has at his or her disposal two sensors to give him or her more confidence in his decision-making process. In addition, we propose several univariate decision strategies which combine sensor characteristics, target probabilities and reward schemes together with deterministic and intuitive operator decision-making parameters. Further, using Chebyshev's inequality we develop a method for selecting the most robust strategy that mitigates poor performance. We illustrate through examples how different strategies will be more advantageous over others depending on the reward scheme and sensor parameters.