After dealing with a whole lot of these gaited horses, in an effort to find what we wanted, we have found more folks loose the gait than keep it, by trotting and cantering their gaited horses.
Very few are even ridden enough to keep them in shape, let alone, try cantering.
It is not old school, it is reality. Unless your a very good trainer, forget the cantering and concentrate on the signature gait of your gaited horse and you'll have a lot, lot fewer problems. Yes, there are always exceptions, but very few.
I never canter mine, why should I, they can rack upwards of 20 mph. That's faster than most canters, and a whole lot easier ride. The wife canters her's occasionally, and just about as frequently as she does, I have give him a tune up, back to his signature gait.
There is a really odd relationship between quality of gaited horse and cantering and/or trotting them. The better and smoother the ride of good gaited horses the worse they are about loosing that gait from cantering, and the harder they are to get it back. Don't know why, but have seen a lot of them completely ruined from it, if fact, that's a good place to find your self some very inexpensive gaited horses, if you can get them back to their signature gait. Sometimes it takes months to get them back, but once their back, and you stop the nonsense, they make excellent rides.
There is a school, that says you can get a tough one to gait, by cantering them as fast as they will go, then pushing them faster they will start. Most of these do not turn out very well, they seldom ever have a nice slow gait. They are speed demons only. Many of the pacing Standardbreds are started like this, and I have yet to see one of these have a nice slow gait.