Countries participating in international competitions should be banned for using unusually harsh training methods. Sportmanship, although extremely competitive, should never be done under duress of threat of punishment. Such tactics are abusive and are not even helpful to the country itself. It makes countries look intolerant and scares the international community away from them.
Yes, countries taking part in competitions on an international level should be banned if they utilize unusually harsh training practices. Harsh training methods can be cruel, inhumane and ethically and morally wrong. It is sad for the athletes who were trained in harsh manners, and it is unfair to countries who do things the right way.
Obviously, some practices are banned in international competitions, like doping, which supposedly gives an unfair advantage. But I don't think we should be sitting in judgment on other countries' training methods if they are not cheating or committing crimes. If their training methods weaken their team then the scores will show it and they'll deal with it. Training for international competitions is grueling regardless. If the training methods are too harsh, let the team handle it.
The only exception to not being banned is if the trainees were being forced through the harsh training. Otherwise, whatever training method they desire to use should be perfectly ok. If one country or team doesn't train and practice the degree that another one does, it is no big deal. The results of training are displayed in the competition.
I do not believe countries participating in international competitions should be banned for using unusually harsh training methods. I say this because it would be difficult to prove such things and impossible to oversee. Secondly, it would be difficult to classify what exactly is harsh training methods and where a line would be drawn when considering them.