Ok, there isn't anything scientific to this, it could be just a happy coincidence. For the past month (several heat cycles) my '05 Tiger has had the engine management light on. The bike runs normally, so after much reading I just ignored it. The light did initially come on and go out after 3 cycles, however it came right back on within a couple of kilometres. Today during a ride, I almost emptied the tank and was forced to buy fuel from a proper filling station (normally I buy regular fuel from our local cardlock, no other gas available for 45kms). Anyway, I filled it with premium fuel and within 15kms, the engine light went out and stayed out for the rest of the ride home (150kms). Now, from what I've read, the '05 Tiger doesn't have any knock sensor however there was a suggestion that the O2 sensor may be able to detect a lower grade fuel. Again, this isn't scientific by any means, but just another possible solution for this annoying Tiger trait.
Sound familiar? I'd like to hear if anyone else has observed this coincidence. edit: red herring, light came back on!