Dumb Little Man has a great article about common home emergencies, including some not so common surival emergencies. Here they talk about snake bites:
Do you rip off your shirt and wrap the wound? Suck out the poison and spit it on the ground? Get out your pocket knife and carefully cut the wound open so the poison can drain?
These are all myths that can actually be quite dangerous and lead to more injury than is actually necessary. If you cut the wound even slightly you may slice tendons or nerves that cause more damage. Tourniquets often lead to the blood circulation being cut off and could lead to the loss of a limb. The safest response is to immediately splint the wound or wrap it in something clean and get to the ER right away.