The shoulder is not a smaller version of the hip. It has evolved to give us much more range of motion and requires coordination of the clavicle, scapula, thoracic spine and humerus. The shoulder is not designed to take the same pounding a hip can take. There is no bony socket to provide stability and it really isn't optimized for ballistic weight-bearing. Joint capsule, ligaments, tendons and muscular coordination provide the stability--not bone. So if you are going to bear bodyweight or greater loads in an open or closed-chain movement, you are going to want to use optimal mechanics to support the weight and give the shoulder the best platform possible. In training, you also want to develop balance of strength about the shoulder and reinforce scapulo-humeral rhythm during training with quality repetition and movement.
Chronic shoulder pain, rotator cuff tears, bicep tendinitis, labrum tears and multi-directional instability are not badges of honor for being an overhead athlete. Nor are they the price one pays for being active. They are the result of poor programming or training progression, doing too much too soon, not using good mechanics, or some combination thereof. Good training and proper progression promote good mechanics and build shoulder health, not chronic soreness. It takes time for the shoulder to adapt and build the capacity to tolerate greater volume and loads.
High volume of certain activities in the weight room can interfere with developing and maintaining shoulder mobility and mechanics. If you don't understand how your programming affects your athlete's shoulders, then you need to ask for help and get a clue. It is your obligation to know how what you do affects the short and long–term physical health of your athletes. And it is your obligation to inform them that more weight or more reps isn't necessarily better at any given point in time.
If your clients have to constantly see the massage therapist, PT or chiropractor for chronic shoulder problems, or they spend an inordinate amount of time with a foam roller / lacrosse ball attached to their arm pit or t-spine, that should be a red flag for you. Yes, injuries and accidents happen, but they should be extremely rare during training in the gym. Ultimately, the shoulder health of your clients depends on your ability to teach them proper mechanics and provide them with quality programming.