You got tricked and felt sore about it afterwards. Your experience isn't unique but to be fair, I'd probably be quite sore too. Not enough to make a post about it as if their behaviour was somehow outrageous or otherwise unexpected but hey ho.
Regardless of the whole strangers-should-uphold-fake-honour thing you've got going on there, or whatever it is you've rebranded your naivety to, I'm more critical of the reliability of the bait you bit. Huge risk for them to open themselves up like that but obviously it worked at least once. Whoever you invaded is a ballsy madman.