I can't imagine even HF sending items that had to
have additional insurance, without a signature confirmation/acceptance.

I have had packages that said on them signature required left by UPS
on my porch. I am almost always home and often UPS will leave
packages on the porch without even ringing the door bell.

Same here. It has happened too many times to me. I've long since given up on
UPS, even for my business. All of my suppliers are told not to ship via UPS,
and any outgoing deliveries are sent via other couriers.