I don't know about an 11 year old. I'm fairly sure I have been left in a hotel room when I was that age, though with my 14yo brother. I've never been a parent of a child that age but I imagine they'd be more likely to fuck about in the room would they not? I'd worry they'd do something dangerous and injure themselves, or just wreck the place, but obviously depends on the child.
I wouldn't leave a baby or toddler in a hotel room to go and have dinner, no.
I guess the policy is in case of fire maybe; the child could get left behind by accident. Or maybe so children don't get left in a room screaming while their parents get pissed at the bar, (absolutely not saying the op would do that, but if there's no policy, then I suppose some parents could).
I used to work in a hotel too and I remember one couple had a baby monitor with them while they had drinks at the bar (it was the couple's wedding). It was all fine and we didn't have any policy about it, so management wouldn't say anything to the couple, but I was very
about it. I couldn't imagine doing it myself.
An acquaintance of mine once settled her baby DS, gave the baby monitor and set of keys to the next door neighbour and then went out for dinner. I found that horrible, but maybe I'm massively overreacting. Wouldn't do it.
I know it's maybe a bit dramatic to bring up Madeleine McCann on these threads, but I do think what happened to her has made me be even more cautious with my DD when it comes to this sort of thing.