You can, just to see if there are any gorilla crabs, etc. But when setting up a tank with LR, I just observe and let it cook in the tank for a while before moving fish and corals over. This gives me an opportunity to observe at night, which when all the creepy-crawlies come out. I did find a few gorilla crabs when I added the Aussie and Solomon rock a few years ago, but nothing else was in the tank, so it was easy to catch them. I personally like all of the funky stuff that comes with live rock, that's what makes it interesting. I also prefer rock from the Pacific, which is where most of the corals and fish come from where we keep, so the bacteria is in line with what we're keeping. I tried some Keys live sand and mud, which gave me whelks, so I spent the better part of a year chasing them down and getting rid of them, so no more Gulf stuff for me. Same with Reef Cleaners, got pyramid snails from them and haven't ordered ever since.