From the Terms and Conditions of the Google Code Jam 2012 Contest, about selection to the Onsite Final Round which takes place in Google's offices in NYC:
By accepting the travel to the Onsite Final Round, contestants represent and warrant that they understand that travel, whether in civilized or remote areas and whether by plane, automobile, boat, raft, or other conveyance, or by foot, on land or water, and in the air, contains some inherent element of risk of accident, illness, injury, loss or death, which may be caused by negligence, forces of nature, wild animals or other agencies, known or unknown.