Weak trunk muscles, weak abdominals and imbalances between trunk muscles groups are not pathological, just a normal variation. The division of the trunk into core and global muscle system is a reductionist fantasy, which serves only to promote CS.
Weak or dysfunctional abdominal muscles will not lead to back pain.
Tensing the trunk muscles is unlikely to provide any protection against back pain or reduce the recurrence of back pain.
Core stability exercises are no more effective than, and will not prevent injury more than, any other forms of exercise. Core stability exercises are no better than other forms of exercise in reducing chronic lower back pain. Any therapeutic influence is related to the exercise effects rather than CS issues.
There may be potential danger of damaging the spine with continuous tensing of the trunk muscles during daily and sports activities. Patients who have been trained to use complex abdominal hollowing and bracing maneuvers should be discouraged from using them.