I am not a paranoid parent, I posted on the other thread that, imo, leaving a baby in an open room in a hotel, where a reception is going on, pissed people banging into things, perhaps even looking for somewhere to have a quick shag, it is not acceptable to leave a baby in these circumstances.
I once put dd to bed whilst we had a BBQ downstairs, the baby alarm was on. One of the guests, our friend, had split up with his girlfriend a couple of days before and she was there, so he got very drunk. He disappeared, I presumed, to the toilet. I heard a noise in the baby alarm and went to check. He'd stumbled into her room, turned on the light, and was lurching over her cot, almost tipping right into it! I screamed at him and threw him out of the room, dh had come up behind me and he threw the guy down the stairs whilst I checked on dd - she was fine! We didn't remain friends with him after that!
Saying that though, I have left them in this house, with the door locked and babyalarm on, whilst we went to the restaurant next door for a meal - we could fully see the house. I've also left her in a locked hotel room with the babyalarm whilst we've gone to the bar. I figure that if there is a break-in or disturbance, I'd hear it as I can hear any movement she makes.
But I would NEVER leave any of my children in a room that is accessible to other people. Even if they are your friends, you just cannot vouch for everyone's common sense.