With Apple Music Family Plan, can two devices with the same Apple ID stream at the same time? Let's say I have the Apple Music Family Plan and two iOS devices signed into the same Apple ID.  Can these two devices both stream at the same time?

Background: All the documentation around Apple Music Family Sharing assumes that each member of the family uses their own device with their own Apple ID.  For us this is not the case.  Family members just pick up whatever iOS device is lying around and want to stream music from that device.
Yes, my wife and I share an Apple ID for Music, since we use iTunes Match as well as Apple Music. It works fine.