Thanks for your interesting responses. Many have said it is completely safe, and have traveled there without issue (most traveled prior to the Muslim Brotherhood or ISIS). One woman said her daughter traveled alone without issue. One man said his son and some friends traveled a couple of years ago. While walking through a crowded street in Casablanca a man came up to him and shook his hand, and when removing his grip, there was a bag in his sons hand. The man demanded a large sum of money for the hash...the boy dropped it, but the culprit summoned a police officer. The officer told the boy to pay for the hash, and then gave it back to the dealer, and told the boy to stay out of trouble or he'd be spending a substantial part of his stay in a Moroccan prison.
It's probably ok for a seasoned traveler to visit, but these boys are 20, traveling with $20,000 worth of instruments, and look American.
They've decided to rent a villa in Sicily on the ocean for $80 euro/night and pass up the opportunity to hit it big in Marrakech Thanks for the interesting replies.