Nay, but do so then; and look you, he may come and go between you 
both; and in any case have a nay-word, that you may know one 
another's mind, and the boy never need to understand anything; 
for 'tis not good that children should know any wickedness.  Old 
folks, you know, have discretion, as they say, and know the 
world.
 — William Shakespeare
  Discretion