Not going to happen. I do agree with you on the pig.Maybe a set eye bolts in some spots. 1 set of holes like they use for the docks or Rainbow Bridge. I have thought about this problem because I have a 75ft houseboat, this feels small now, HA!. I have broken anchor lines and pulled anchors and boulders in big wind storms. I have been doing this for over 40 years and have seen dock's break in big weather.
NPS drills holes already along with the vendors. I could see this becoming a issue, because you can't say "well, some animals are better than others" (except for Pigs, because they have the bacon inside).
If they are going to allow pinning, then put the pins in for anyone to use.