Which of the following is not a key element when planning a safe hunting trip?

The decision to select hunting alone without backup as the option that is not a key element when planning a safe hunting trip is well-founded. The importance of having a companion when hunting cannot be overstated. Hunting with a partner is a critical safety measure, as it provides an additional layer of support in case of emergencies. This could include dealing with injuries, navigating unfamiliar terrain, or even assisting each other in tracking and retrieving game.

In contrast, leaving a detailed hunting plan, informing others of your location, and choosing the right equipment are all vital components of a safe hunting strategy. A detailed hunting plan helps ensure that others know your intentions and can react appropriately should you fail to return as expected. Informing someone of your location enhances safety by allowing others to locate you easily in case of an emergency. Selecting the right equipment ensures that you're adequately prepared for the conditions you may encounter, further enhancing your safety during the hunting trip. Thus, the absence of a backup partner significantly compromises safety and is regarded as an unsafe practice in hunting.