Originally Posted by jtrzerocool
why is it so illegal??
There's a little more behind such laws besides thievery.
One aspect is that many states/countries have laws against removing lifeforms from the ocean such as fish, invertibrates, etc (Although some can be taken with proper licensing) ... The idea behind it is to peserve ocean life from indescriminate harvesting so that it can flourish naturally.
In essence, a person can only remove dead things (abandoned shells or dead stars, for example) from the ocean. It certainly could be argued that rock would have living things on it and if it did, it would be a violation of any marine life species protection laws to remove it from the ocean.
As for live rock bought and sold, much is "farmed" in that rock it placed in the water for a couple of years, then harvested. Also, much like fishing, legitimate companies are licensed to take rock, and also have a limit on how much they can harvest.