Never really seen this before. DL134 and DL16 (DTW-AMS/LHR) are each delayed tonight at DTW due to flight times being so short they'd get to their respective destinations "during curfew," according to gate staff.

I am on DL134 and know that DL132 departed earlier and is arriving more than an hour early at 4:27a local time in AMS. Clearly there's some way to have an exemption to arrive before a certain time or DL132 would never be allowed to operate as it does, but I wonder how the curfew is enforced. Anyone know how it works or if perhaps there's something else at work, here?