Can you get caught easily for using frostwire mp3rocket or LimeWire?

Not easily, since IP tracking software isn't fool proof, so it isn't that easy to get caught, but if you take enough songs, the trackers will be on your case, and you will get caught in a matter of time. If you just take one or two songs, then there is a less likely chance that you'll get caught, but it still may happen. Just don't use them to avoid getting caught at all.