Here's a Swedish news article about Johan Sundström (19, year old, 2nd round draft by Islanders), who suffered a serious concussion during a Elitserien game in Sweden after taking his team mates shot to his head (the article includes video of this). He was helped out of the ice but for whatever reason allowed to continue the game after getting 8 stitches. This happened on Thursday. On Saturday he played another game for Frölunda. The concussion was only diagnosed by national team doctor after Sundström had arrived to the training camp for upcoming Juniors national team, and he was immediately banned from playing. According to the doctor, the Swedish Ice Hockey Association has a rule, which requires player to be symptom free for 6 days before being allowed to train.
After all the talk about concussions lately, one would think that some progress has taken place, but this doesn't sound very good. Either he magically didn't have any symptoms before arriving to the camp or he did have the symptoms, but the team (Frölunda Indians) chose not to care about them.