I can't answer for CSA but at CN they are along the outside wall of the dive building. You have to sign for a key and there is no cost IF you don't lose the key. If you do; there is a charge but I can't remember what. I assume they are similar at CSA.
Our wetsuits would get hung on a rail outside to dry along with the DM's wetsuit and the guys would take them inside when they closed up for the night so we didn't have to come back at closing. Such wonderful service.
Couples Negril - September 2011, 2012, 2013 and have just booked 2014
Scuba Club Cozumel - Jan, Apr & Nov 2012 and Jan & Nov 2013
Cobalt Coast, Grand Cayman - May 2013
Retiring & moving to Cozumel, Mexico in early 2014