Ah but it is also a faux pas to apply social ritual rules outside of the formal dining areas of the house. Nobody's tamping down the ground coffee in their moka pot in the receiving room or the dining room.
If a guest is invited into the more intimate areas of the house like the kitchen, (food safety issues aside) they can no more object to what they see than a theatregoer given a backstage tour could complain that the actors are out of costume.
It is among the kind of people who use the terms "faux pas" and "social ritual" and who think it's possible to use a moka pot in an "embarrassing or tactless" way.
If I'm having the queen around for high tea it might be a "faux pas" to serve biscuits in a plastic packet or tub, and proper to arrange them artfully on a china plate. But if we're following that ritual, the queen absolutely does not enter the kitchen.
If on the other hand the guest wants to engage in the "we're just regular people" ritual they gain the right to enter the kitchen - but lose the right to complain when the biscuits are served straight out of the packet, or to use the term "faux pas"
If a guest is invited into the more intimate areas of the house like the kitchen, (food safety issues aside) they can no more object to what they see than a theatregoer given a backstage tour could complain that the actors are out of costume.