I feel sorry that Sheryl didn't feel having good experience, but I do have to clarify things here:
1. "Two different men showed up, one the first night, and a different one the second night." -- I am totally SHOCKED by this untrue statement and surprised how it can be made up this way. I stayed there for the two nights and did not allowed any other MAN to enter the home during the whole course except my girlfriend (she stayed with me for the second night). The other person living there can prove this for the first night, and my gf can prove it for the second night. Sheryl saw me check in and out on both days, so I cannot understand why she would write like this.
2. "he waited til lights out, and snuck a woman in" -- This is purely her guess and she didn't ask me for any explanation. The fact is, my girlfriend and I hang out that night till late; she lives far and there was no bus at that time. Only till then, I decided she could go and stay with me for that night. When we got back to the house, lights were out, which suggested to me Sheryl has already slept. I didn't try to wake her up to tell her this for politeness. However after a while I received a phone message from her asking when I will check out tomorrow. She didn't mention anything about my gf or anything like a different man in the house. I immediately replied and tell her that my gf has come with me, and ASKED if it was OK for her to stay. She said I should run that pass her first and then said OK but there's extra $20 charge. I agreed. The next day I cleaned the room, checked out around 11am and left $20. Sheryl saw me check out but didn't say or ask anything. (why not ask me if she doubted the person she saw checking out is not the one checked in?)
3. she used the word "lying". I didn't lie anything to her. I initiatively told her about my gf's come (immediately after I'm aware she was not asleep) and asked her if that was OK. (I still have the phone messages that can prove this; if Airbnb is interested to check, I'd be happy to show) I would also be interested if Sheryl can explain on what matter I lied to her.
In sum, this is bad experience with me too. Yes, I should ask the host first before letting my gf in, I agree and I do apologize if that brings any inconvenience. But consider it was late in the night and lights were out (which suggested to me the host was already asleep), it's hard for me to decide to wake her up. Plus I initiatively and immediately informed her when I'm aware she's not in sleep. Everyone can have emergencies and unexpected situations, and that's when communication is needed. I already had communications with Sheryl and we achieved agreement with extra $20 for my gf to stay. I couldn't understand why a two-men story was created and 'lying'/'snuck in' were used later, given all the facts above.