1. The individual could end up with a form of liver poisoning, or other disease/sickness. When an individual has a high tolerance of alcohol, having just a small amount of alcohol to drink "doesn't do it for them" anymore. A person that has a high tolerance of alcohol more than likely drinks often, or excessively. Having such amounts of alcohol in the body will eventually deteriorate the body in some way.
2. A person that has a high tolerance of alcohol may have far many more drinks than the average Joe, and not be nearly as drunk as average Joe. so if he were to get pulled over, he would more likely fail the breathalyzer test, even though he may not be drunk.