Why is it when liberals are asked if...?

they think it is a good idea to do what Bush is doing to combat terrorism through the patriot act, they respond with that Benjamin Franklin quote of, "If someone sacrifices freedom for security, they deserve neither." But when talking about global warming, many of them start yelling at cons. for driving hummers or SUV's and saying that contributes to global warming and we should all stop this. So isn't having people stop driving hummers and SUV's for this reason the same as sacrificing freedom for security?