It's fairly well-known that (at least in 1.11 EE / 1.6 CE) you can bypass tax rates by utilizing a Zip + 4 (in USA) zipcode. I have tried to add a wildcard to the end of the 5-digit tax rate definition (which in my opinion should have worked) but that proved fruitless.
I found a suggestion to apply a core patch here which involved something to the effect of:
line 235 replace:
$postcode = $request->getPostcode();
$postcode = substr($request->getPostcode(),0,5);
Copying this to a local/Mage wouldn't be the end of the world - and would save us tax headaches. But I'm not a fan of that method.
How do you work around this issue?