If you’re happy just being “a rider,” (no condescension implied) it isn’t any big deal at all. If you’re trying to follow the path of Dressage Righteousness, it begins to matter.
Let it be said that some people interpret the stated abhorrence of hand riding to mean you simply aren’t supposed to do anything with your hands when you ride. The result is riders who drift aimlessly through 20-meter-long trot to walk transitions or who ride endless circles pushing their horses forward into nonexistent contact and hoping they will magically come onto the bit.
For the good of your horse’s movement and his mental state, you should learn as much about back-to-front riding as you can. This includes doing exercises where you figure out how to use your body language to make a transition or a turn. But in so-called “real life,” you’re allowed to incorporate the use of your reins as modifiers to help explain what you seat and legs are asking.
As a rule, your aids should begin from your core muscles supported by your legs. Then, in the next instant, a rein effect acts briefly—just for the duration of a footfall—to limit or redirect the energy you’ve created. By and large, your hands shouldn’t be speaking louder to the horse than your pushing aids are.
We also talk about a “receiving hand.” You ride to the hand and meet the horse with the contact—otherwise it’s like pouring water into a sieve and wondering why you’re not collecting any. The image I used in DRESSAGE Unscrambled was the old Wurlitzer juke boxes with the bubbles flowing throwing those lighted tubes that surround their front face. Picture the reins as those translucent tubes. If the bubbles are constantly flowing from the bit towards your hand, you’re hand riding. If you can make them flow towards the bit, you’re in business.
One further thought: To every rule, there are exceptions. If you’re dutifully trying to ride back to front as your horse is careening towards a bottomless abyss, it might just be time for an unclassical moment of politely ripping his face off in order to live to ride another day! In such circumstances, don’t even bother to feel guilty.