No kidding. I cringe every time I see a stainless steel sword being used for any kind of impact. The steel itself is often times too brittle, or of inferior construction and consistency, and can easily snap.
Even non-contact work with the cheap stainless sword can be dangerous, regardless of the level of training that one has had.
Many of those swords have a "rat tail" tang, which is nothing more than a thin, threaded rod that extends through the bottom of the handle, and the rat tail tang is welded to the blade. The tang is retained by a wing nut that screws into the bottom, and tightens it against the handle.
Often times, the welding is substandard, and it's entirely possible that mere swinging can result in the blade severing from the tang, creating a VERY deadly flying object.
When first learning how to use a sword, follow Tulisan's advice. Start with either a bokken, or a shinai, and get some training from a qualified individual.