To be clear, I think you meant to say ". . . if the tension was released and NOT recocked before [attempting] fitting it to a camera" and that could damage both the lens and the body mechanisms.
Of course, even if you store them cocked like in the case or bag, there's always a chance that they could trip, say from being moved around or bumped so it's best to always check both body and lens before trying to reattach one to the other.