Is it a good idea to do rotator cuff exercises (as a means of prevention of injury) using weights prior to doing exercises that utilize the rotator cuff such as the shoulder press or bench press and others?
It is a very bad idea. The main role of the rotator cuff muscles is positioning the center of the Humerus head in the precise place during each movement (avoiding the dreaded humeral head migration), so that the action of the "big" muscles (pecs, lat, deltoid heads) does not result in soft tissue impingement and the rotation takes place smoothly.
By exhausting those tiny muscles before the big exercises, they will be less ready to protect your shoulders. Really, it is a very bad idea. It is asking for injuries. Just read here
Researchers have established that superior migration of the humeral head increases after fatigue of the rotator cuff muscles.
Rotator cuff exercises, if any at all, should be done after your workout. And also, you have to do a truly big effort in abandoning your bodybuilder instinct during those exercises. They must be done (in case you still insist in doing them) with very light load, high slow reps, and trying simply to get a bit tired, never to exhaustion.
If you are young and you haven't had any shoulder issues, your best way of protecting your shoulders is by having perfect form during your normal exercises. Also, avoid behind-the-neck press/pull exercises. And do not be very obsessed with working your shoulders separately very often.
I myself have become very interested in this area, based on my research I have discovered that Massachusetts General Hospital actually DO recommend doing warm up exercises under the heading Prevention of Injuries in Weight Training
The source can be found here:
I think that you need to consider whether or not the rotator cuff exercises before lifting are a light warm-up or performed to the point of fatigue.
If the exercises fatigue the rotator cuff muscles, then as @Mephisto cautions, the humeral head will migrate superiorly especially with overhead exercise such as the shoulder press. This is an unwanted consequence causing less room for the cuff between the acromion and humeral head.
Dr. Wickiewicz did an xray study looking at the effect of rotator cuff muscle fatigue and humeral migration. He found (pg 6) :
that the effect of exercise fatigue in individuals with “normal” rotator cuff musculature will cause the humeral head to superiorly migrate in the glenoid during overhead motion, mimicking the same superior humeral head migration that occurs in individuals with rotator cuff pathology.
The fatigued rotator cuff could not “offset” the strong pull of the deltoid musculature previously described, resulting in a superior migration of the humeral head on the glenoid during overhead ROM.
After fatigue, excursion of the humeral head increased .... With the initiation of abduction, the humeral head demonstrated significant superior migration or translation in all positions tested.
This result has important implications for conservative treatment of shoulder impingement and underscores the importance of rehabilitation to maximize the endurance and strength of the rotator cuff musculature.
However, if exercised to the point of fatigue, prior to weight lifting or overhead activity, these muscles will not offer joint protection.
The Massachusetts General recommendations that you cited are
as a warm-up using light weights.
The rotator cuff is collection of four tendons and muscles. Most people don't target them until they've had some form of injury to the area. They are typically exercised using bands, towels, cables, stretches, and very light weights. If you've had previous problems with your rotator cuff, it's not a bad idea to warm up first. Make sure to perform any exercise with strict form. If you currently have problems with the RC, you should seek the advice of a physical therapist.