Let them in, offer a drink and be cool. Buyers are human too!
in all seriousness, just be nice. I had an amazing time as a buyer at a sellers place. I ended up there most of the day we had some nice coffee and a couple of cocktails. Listen to music, put the world to rights.
he’s the one who’s probably slightly more at risk. It’s far easier to take money than run off with heavy hifi gear.
you will get a read on them within a few minutes and just be careful but nice. Who knows, could be a long friendship over a shared interest.