He was just covering for patrick.
LLS
Ah yes... interesting comments in a Wiki article about William Kennedy Smith. Notice that Patrick was there with William and his father, Teddy.
"The incident began on the evening of Good Friday, March 29, 1991, when Smith, then 30 years old, was in a bar (named Au Bar) in Palm Beach, Florida, with his uncle, Senator Ted Kennedy, and his cousin Patrick Kennedy. Smith met a 29-year-old woman and another young woman at the bar. The four then went to a nearby house owned by the Kennedy family. Smith and the 29 year old woman walked along the beach. She alleged that Smith raped her; Smith testified that the sex was consensual. Although three women were willing to testify that Smith had sexually assaulted them in incidents in the 1980s not reported to the police, their testimony was excluded.[2] Smith was acquitted of all charges."