More and more sensor networks will be deployed in the place where people are living, studying, and working. These sensor networks bring us the convenience of accessing information anytime and anywhere, whereas put our voice, motion, or even body temperature under surveillance. Under the circumstances of pervasively deployed sensor networks, people will have a dynamic concern about their privacy. At the same time, sensors will become invisible or should be hidden due to the privacy of themselves. This paper discusses privacy issues in pervasive sensor networks and proposes a general scheme for people in the environment of pervasive sensor networks, so that they can be aware of whether they should be alert on their privacy activities. Based on the protocol of secure two-party point-inclusion problem, the scheme has the characteristics of generality and confidentiality.