"What goes on tour, stays on tour"...
...just about sums up the 'Kai Tak Rules'. As a member of rugby tour, you may sometimes be privy to information that could be very useful if it fell into the hands of the enemy. You must therefore never discuss anything that happens on a rugby tour after going through immigration at Kai Tak Airport (or Chek Lap Kok for post July '98 tours).
Remember there are also the Shun Tak and Low Wu rules for tours to Macau and Guangdong.
If in doubt - deny, deny, deny, and remember what happened to PB Jonah!