In embodiments, a spreader frame for hoisting a container having a lifting block is provided which includes a rigid frame structure, a twist lock received by the rigid frame structure, the twist lock being rotated relative to the rigid frame structure between a locked position to engage the lifting block and an unlocked position to disengage from the lifting block, and a safety feature which cooperates with at least one of the rigid frame structure and the twist lock to retain the twist lock in the locked position from being rotated relative to the rigid frame structure absent personnel changing a position of the safety feature.