Which type of lanyard snap hook is more prone to allowing 'roll out'?

The non-locking snap hook type is more prone to allowing 'roll out' because it does not have a mechanism to securely lock the hook in place once it's engaged. This lack of a locking mechanism means that any movement or shift in the attached load can cause the hook to unintentionally open, thereby allowing the connector to detach from the anchorage point.

In contrast, locking and double-locked snap hooks have mechanisms designed to prevent accidental disengagement. These types of hooks require intentional action to open, reducing the likelihood of roll out. Spring-loaded hooks, while they may be safer than non-locking hooks in certain applications, typically do not provide the secure closure that locking mechanisms do. Thus, the non-locking design presents a higher risk of potential failure during use, particularly in conditions where dynamic movements occur.