Welcome CJS to ECN.
There is no requirement protect the panel twice, as you said it makes no sense.
There is a NEC requirement to have a disconnecting means in a separate building or structure. Check out 225.31 & 225.32.
The garage Delectric is taking about is "40 ft. away" so you need a disconnecting means at that structure.
The easiest way to meet that requirement is a main breaker panel, but you could use a disconnect switch ahead of a main lug panel.
[This message has been edited by iwire (edited 09-16-2004).]