[xAndrewx]

Because you're referring directly to the player, I'd put the check INSIDE the class. Otherwise you're defying the point of player classes.

Inside the 'foobar' class I'd do the following

  //Call the check on login
function onCreated() {
  this.createVariables();
}

  //Do the check here
public function createVariables() {
  if (this.foo != null && this.bar != null) return;

  this.foo = 1;
  this.bar = 2;
}