I have not hosted anybody on Warm Showers for 2 years. I get requests and just cant bring myself to open my doors to anybody anymore. I signed up for warm showers in 1999. It was a lot different. I have never used it to find myself a place to sleep because back then when I was touring a lot, there were no smart phones, and it was a logistic nightmare.
However, we have hosted dozens of people at our house. We had a standard formula: if they were riding across the country, ask them if they want to go to get dinner somewhere and buy them dinner. If they wanted a day off, give them the keys the house and let them do whatever. Even without warm showers, the generosity of strangers shown to us over the years was amazing and we felt as if we needed to give back.
Then in 2017 we had a single male show up. He was "riding cross country." He had planned his route months in advance. From the minute he arrived, there was something off about him, to the point where my wife was like "I am not dealing with this guy..." and didn't go out to eat with us. He was ungracious at first, insulting how hot our house was, among other things. After spending the evening with him, I had "bad vibes".
That night, my wife and I laid in bed googling him. I found a bikeforums thread that he started that was all about his trip. There were a few people in the thread that seemed to be making a hobby of disproving things that he said. It was interesting to say the least. I found his instagram where he mentioned camping with a woman that he had ridden with for several days. I found her instagram and she mentioned being robbed by a guy that she had ridden with for several days. I locked our bedroom door and braced it. I messaged her and asked her if it was him. She said yes.
The guy took a day off while staying out our house. I didn't give him a key. I was skeptical of everything that he said. Reflecting on it, he was either a chronic liar or a sociopath. He stayed another night. We were forceful with rules and boundaries to keep him out of our house as long as possible. He stole several items from us.
I turned him into warm showers and they canceled / suspended his account. He messaged me and called me names. The guy on bikeforums sent me an article from a newspaper in new England about him that was a feel good story about a guy riding his bike for charity. He was wearing my stolen item in the photo.
Keep your guard up. Just because somebody is on a touring bike does not mean that they are your friend.