Hey Evil SH,
Yes, they do exude a chemical attractant! Sarracenias in particular do. Not only does it attract them, it intoxicates them. I can go out on my deck and watch goofy, drunk flies play around on the pitchers, so oblivious I can practically touch them.
CPs don't need much in the way of food, but if you put them outside (provided they can take the weather, and most can), they will catch plenty. You can also just grab a bug or two and feed them yourself. My experience is that the Sarracienias and Droseras are the best insect catchers.
Capslock