I've been both hosting and attending listening sessions for many moons sometimes to hear new music and other times to compare equipment.
Before purchasing my current speakers, Dutch and Dutch 8C's, I had a pair of Morrison Omnis on one side of the room and Janszen ESL's on the opposite side, both of which were hooked up and could be switch on or off quickly. By turning the listening chair around one could easily compare both sets. I had several audiophile and musician friends come over to listen and help me decide which speakers to keep or sell.
When living in Richmond VA I was in an audio club that would occasionally go to members' houses to hear their systems. We did a shotgun start so not everyone was at one location at any time. It was both fun and fattening

One member had a fortune invested in his system in a custom built gigantic special purpose audio room. He had 10 Krell amps! The electric company actually installed his own electric pole in front of his house. That adds new meaning to the term dedicated line. Lol
Al