Your last bit of code confused me....

return 1 && $a && $b;
[download]

is identical to

return $a && $b;
[download]

is identical to

return 1 && 1 && 1 && $a && $b
[download]

So I don't follow your last paragraph...

Update
Were you perhaps thinking of:

return $a && $b && 1;
[download]

which will "coerce" all TRUE responses to be 1 instead of the value of $b?

-Blake