I have done it on several occasions. Never without a redundant air source and safety gear, ie. wreck reel, lights, pony bottle, etc... I also think the course is a great way to advance your skills even if you never intentionally dive solo. Ever find yourself more than a dozen feet away from your buddy? What about getting separated in poor vis or heavy current? And what about the "Buddy" you get hooked up with on the dive boat. Is he/she really qualified to save your a-- should something really go wrong? I make it my business to be prepared to help out anyone I`m diving with or near, but I will not stake my life that anyone else is willing to do the same. I think that diving each dive prepared to be a solo is a good idea, it may help you someday, and it can never hurt...