The lazy jacks put a very low load on the point they are attached to. All the LJ's do is keep the sail from falling off the boom as it's lowered. Suppose if someone was to try and hang on them it might be an issue but because of the small diameter line doubt anyone would do that. I can stand on my spreaders without an issue. Haven't gone out to the tips and jumped up and down but you aren't attaching the LJ's out there, in case. The spreaders are seized to the shroud with wire that mainly keeps the shroud in place on the spreader and offers little resistance to vertical load.

FWIW, my LJ's that are attached to the mast do not bang when stowed against the mast. Possibly because they are right up against the mast and are only 1/4' line, they don't flail about like a halyard that is larger diameter and offset from the mast at the top.. Hate clanging halyards and would have been on the LJ's immediately if they caused a noise issue.