This is a very dangerous thing to think. Any of us can make a human error mistake anytime. As a result, we should do everything in our power to keep such a mistake from happening. Things to consider include, tying knots at the end of the rope before belaying or rappelling, using an autoblock for a rappel, wearing a helmet, etc. In this blog post, we will go through the steps required for a safe and fun climb.
Does the belayer need to be tied into a bottom anchor? The default answer is, "yes." If the belayer is not tied into a bottom anchor, you should be able to articulate why.
2) Belayer -- Is the belayer's harness on correctly? Is it doubled-back? Is the belay device threaded properly? Are you using a locking carabiner on the belay device? Is the carabiner locked? Usually a visual check is not good enough to prove that a locker is locked. It's always good to give it a quick squeeze check. Is his helmet on properly? Does he have a nut tool to remove gear if he's going to follow?
3) Climber -- Is the climber's harness on correctly? Is it doubled-back? Is the belay device threaded properly? Is he tied-in properly? Is his figure-eight dressed and neat? If he is leading, does he have the rack? Is his helmet on properly?
4) System -- Is the system closed? In other words, have you made sure that the end of the rope is either tied directly into the belayer or that there is a knot at the end? Open systems are responsible for a large percentage of climbing injuries and fatalities.
5) Commands -- Are you both on the same page as far as commands are concerned? Many people use different variations of commands and it's not a good thing to get them mixed up. Do you have a communication plan for places where it's difficult to hear?
6) Multi-Pitch -- Do you have the climbing topo? Do you have food, water and clothes for the day? What is the weather forecast? Do you have a second rope in case you need to descend in an emergency? Do you have extra cordage and sling material to leave behind? Do you have a strategy?
Climbing is a game with few rules. One of those few is to make sure that you are completely prepared for the situation at hand. Go through the check-list every time. It could save somebody's life...
--Jason D. Martin