I detest when people give bad info.
PROVE to me why rabbits receiving a balanced diet "need salt licks" if you will.
Here is what I found
Vitamins, Salt, or Mineral Block These are not necessary if the rabbit is getting even small amounts of pellets. Rabbit Care Resources - Dane County Humane Society Best Answer - Chosen By Voters No, rabbits do not need extra salt in their diets. A good diet will contain all the necessary sodium (salt) a rabbit needs. Yahoo! Answers - Do rabbits need extra salt in their diets? The 3 most important foods for a rabbit are hay, hay, and HAY! Contrary to popular belief, rabbits do not need salt licks, vitamins, or hard wooden objects to wear their teeth down. Petfinder Library Avoid feeding treats that are salty or "sugary"...You also don't need to use a salt lick or block if you're feeding pellets. The pellets will contain all the salt bunny needs. Rabbit Diet Information A salt lick is not needed for rabbits RABBIT PAGE: littlecrittersvet.com
I found nothing that says they are dangerous except in one of the pages listed above that made mention of salt poisoning, but I found may references that say they are not necessary and many that said you can use them but that a good diet makes them unneccesary.
I will be happy to post this question on Etherbun to get a better answer if people are interested in more info.