If a 3/8” shackle has a safe working load of 2000lbs (well within any safety ratios) - why would the back of the packaging say it’s not for overhead lifting / support of human weight? (https://www.lowes.com/pd/National-Hardware-N100-356-V3251-3-8-in-Shackles-in-Stainless-Steel/5000052457)

Is that just a legal disclaimer to avoid lawsuits if something happens?

The setup in my mind (so far) would be U-bolts clamped to and I-beam with uni-strut. Strut channel nuts that connect to a forged eye bolt rated for 2200lbs and then have the D shackle connect to wrist cuffs. (All hardware would be a mix of 1/2” or 3/8”)

I’ve done enough rigging for work to feel somewhat confident in this approach but I’m open to having any holes poked in my thought process.

Edit: added links to products for reference