Oh ####, I just remembered they installed those bike only barriers on 1st street and 18th avenue to prevent thru-traffic. I believe it's only temporary (at this time as they assess it and receive comments) but if they do make it permanent, then this decision is even all the more baffling.
So maybe once in a decade during some amazing promo you'll have a car waiting in line on 18th avenue where thru-traffic is discouraged?
From my amazing photoshop skills here you can see the red and yellow are how cars must travel as the barrier prevents them from going straight through that intersection. The blue is (was) the drive-thru, keep in mind that it really does need about 10 cars before it would get onto 18th avenue.
Again this assumes they keep the layout relatively the same.
I understand that the drive-thru is not the only reason for the denial but really it is a red herring being used. There's really no impact or safety concerns from it.