The terrible balloon accident in British Columbia, see video here raises a long debate over whether certain activities should be treated as strict liability offenses. Under the common law and the Restatement of Torts, certain activities are so dangerous that they are classified as ultra hazardous or abnormally dangerous — leaving the operators strictly liable for injuries. Air flights long been classified in this sense, though that is a bit dated given the safety record of airplanes. However, ballooning would likely still fall into this category. Of course, there remains the question of assumption of the risk in such cases, which historically is a complete defense.