Does the "fruit of the poisonous tree" doctrine affect the exclusionary rule in this case?

The "fruit of the poisonous tree" doctrine effectuates the policy behind the exclusionary rule. See Dunaway v. New York, 442 U.S. 200, 217-18, 99 S.Ct. 2248, 2259, 60 L.Ed.2d 824 (1979). The policy would not be advanced by exclusion in this case. Because incidental observations which police have in mind when detaining a suspect are not objective, suppression of such observations will have no deterrent effect on unlawful police activity. The exclusionary rule imposes large social costs and should not be applied where, as here, it would serve its remedial objectives weakly, if at all.