I think it's a huge crapshoot. My SO worked as a waitress in a Denny's in college, all the servers mixed the decaf regular pots so often that it was almost comical. The patrons would get a 50-50 caf decaf, the other waitresses would always say.

One of my relatives would always bring her own decaf packets to her local cafe and ask for hot water. When one manager asked her why, she said everytime I've ordered cafe here, I've been wired for 2 days straight, are you going to make me a fresh pot of decaf? The manager replied No. She said then please pour me a hot mug of water.