Originally Posted by MSPeconomist

In the past, the main DTW club did stay open late when flights were delayed, as did one club at MSP. I remember the PMNW DCA WC staying open late one evening shortly before the gates and lounges were consolidated.

I wouldn't necessarily expect this for one small flight with just a few passengers in the lounge, but I do expect it for a long haul flight or when multiple flights are affected.