Yesterday I finished the book "At The Zoo" by Dr. Phillip T. Robinson, DVM from the San Diego Zoo (Columbia University Press/2004), and in it he details some of the problems with tranquilizing zoo animals. Starting mostly in chapter #9 (Holding the Tiger) Dr. Robinson tells of the problems of darting or otherwise
"chimical restraint" (as it is know in the zoo business) of the aminals for moving or for medical treatment. The big problem being that even now the exact doseage of tranquilizers is not an percise science.
Concerning Bigfoot, we do not know the dosage needed for darting one. We do not even have a real grasp on the weight of the animal to have a good drug to weight ratio. And some zooalogical drugs are species spaciffic. So if we dart a Bigfoot, we could kill it. Or with too little drug the danger turns to who is working on the Bigfoot as it unexpectedly wakes up.. In that case we would have unimpeachable evidence of Bigfoot ....... but it might not be sutable to been shown on CNN.