THE failure to prosecute the Sevens streakers has left the Hongkong Rugby Football Union (HKRFU) feeling exposed. Three men and two women who bared their bodies in front of 33,000 fans at the Government Stadium were let off with warnings after the police decided it was not worth the courts' time prosecuting them - even though previous offenders had been fined. That decision has upset a ''disappointed'' HKRFU that had hoped to use the event in the half-rebuilt stadium as concrete evidence the territory should be the site of any future World Sevens championships. But as an estimated 65 million people watched worldwide on Sunday, and with the influential chairman of the International Rugby Football Board, Sir Ewart Bell, in the stadium, streaker after streaker broke over the barrier and dashed across the pitch. HKRFU chief executive officer Mr Dave Roberts said: ''It is not up to us to decide what action the police should take, but I have to say that we were disappointed the streakers were not punished.'' Looking ahead to next year, Mr Roberts said it was not a practical solution to put a high fence around the perimeter. The concept of the redesigned stadium is to allow spectators to leave as quickly as possible in case of emergency, which means they have to have easy access to the field - a fact that put paid to P.S. 's suggestion of installing razor wire on the barrierfence as a deterrent.