I also think there's a difference between maybe doing this once in a lifetime there is risk but it is low and setting it up to do it regularly. I can definitely understand the temptation, and I confess that we've stayed in pubs where the rooms are behind a locked door, right above where the tables are, and where we could see the only exit, and have had a meal in the restaurant there (gasp!). With the monitor. I have friends, lucky friends, whose houses are big enough that were closer to the room than we would have been at their house - no one would doubt the safety of eating in the dining room of a large house, 30m from the childrens' room, maybe EVEN without a video monitor.
So it's kind of context-dependent. The fact that you're off your property seems to matter, but would it really be less safe than at the end of a 50m garden, say? And most people would be fine with that since it's not "public". I don't think the "public" comprises much additional risk, really, but why does it, or doesn't it? After all, you could have DC running a bath / walking out the front door/ turning on the hob / laundry marker havoc if you were eating dinner on your lovely stone patio 30m from your back door, with or without your video monitor. Or in your dining room with friends enjoying loud-ish conversation, if you had a large enough house not to hear the DC.
Anyway. I get why you're tempted. I wouldn't do it and I certainly wouldn't want to see someone set up the video etc system to do it regularly. Opinion here suggests you'd have trouble enjoying your evening. But: is the actual danger really more than sitting in a big house/ big garden, especially if to do that, we wouldn't think you'd need a monitor? If not, then maybe we should all be very glad we don't have big houses or gardens because we'd want to stay within 10m of our babies anyway :)