As for 3-day field rides, management has the authority to demand them all they want, but it's a shame they don't have the wisdom to see that they hurt business . When a doctor sees a manager next to the rep at the reception window, they are far less likely to give time them. It's really that simple. The fact that it's the best way for a manager to coach a rep is wholly unpersuasive to the Doctor. As they see it, they're treating patients, not running a training center.
Yes, reps need to be managed. So DSM's should use role playing, business reviews, product-knowledge quizzes, and sales metrics, etc.. to gauge their effectiveness. Just quit following your reps into the offices - the time when you could get away with that has come and gone. Keep at it and soon ALL offices will disallow rep access.