mingkee said:
some churches and cinemas having "blocker" installed, however, outgoing calls can be passed in case of emergency

I can halfway understand that, BUT, unfortunately, 911 calls are not the only type of emergency calls I still don't like it. I myself am a churchgoing person, & I know to put my phone on silent/vibrate when entering a house of worship as well as a cinema. People should do this regardless.

There is another problem with using the jammer in those buildings though: I used to work for ServiceMaster (a disaster restoration company) where I had to be on call 24/7 to take care of peoples houses that flooded. What about service professionals who are on call 24/7 & may need to be reached when at church or at the movies. I used to have to leave restaurants, movie theaters & even church when I would get a call b/c somebody's house flooded & I had to go to work. A jammer would have prevented me from being reached by my employer, thus delaying getting professional help on site for the homeowner in need. What about the guy in my Bible Study group from church who is an EMT? He too carries a cellphone & can get a call at any time to go to work. Peoples lives hang in the balance in his case.

There are perfectly good reasons why the FCC has outlawed such devices & put such steep fines on those who do use them. I hope this helps to clarify a bit.