I like how badges are awarded here and that a trust level system 0-3 has been built into the design (Understanding user trust levels).
Something like this could easily be used as a foundation for scoring the reliability/trustworthiness of people. Once you have hosters and travellers reviewing each other more frequently, then that could also feed into a person’s score. That way, you could eventually gauge - as best as is possible on the Internet - what sort of person the coucher is…and also, let’s not forget, what sort of person the host is.
I think everyone is going to have their own idea on this. I’m the opposite to you: boundaries for me can immediately create the sort of relationship that you repudiate (capitalism and consumerism), as it sets up a master/mistress of the house - newcomer or at least landlord/tenant relationship. I basically just apply the same rules to couchers as I do to housemates: we’ve both got equal right to be here, so let’s make this work. The difference is that you get to pick your couchers, not always your housemates!