That depends on the species of crickets used. Acheta domesticus (house cricket) and Gryllodes sigillatus (banded cricket) are the two most common crickets used as feeders, and neither will attack chams
These critters are quite capable of biting. But they are not strong enough to damage the human skin. These can be found anywhere from your living room, your garbage bin to your garden.
But i am not sure if they can bite chameleons, @ERKleRose your probably right