And yet I got a house patch 2.4, auto demolition got introduced in 3.1, still have a house and still avoided losing my house. A whole year of no demolition to suddenly having one and still have a house. Imagine that.
If they're level 15 and got the gil and they are suddenly dropped into a house and must maintain it or lose it, yes. Doesn't matter if their main goal is to level up. If their interest is in keeping this house, then that answer is yes.
Getting outside information on a game has been around a very long time. Yes, some people like doing things blindly (like content - I like blind content), but I'd almost say with confidence very few people play games, especially MMOs, without an outside reference on something. A lot of people look up primals, savage and even rotations for their classes. People look up little fluff things like where to get minions (because unless you know where they come from, you're probably looking up how to get one of them). People reference glamours and even a list of FFXIV housing furniture to see how they look - that's still all outside referencing. Technically, reading the patch notes is an "outside source" because it's not within the game.
Yes, we have those things because time and again people have proven to show just how utterly irresponsible they are. They weren't always there - I remember them not being there and being subsequently annoyed they suddenly started popping up. This is where I wish I had that one person's signature I've seen where it says "WoW expects competence. SE (or was it FFXIV) is pleasantly surprised by it." Pretty aptly sums up the two communities, it seems.
To sum up what I'm trying to say:
Add in pop-ups that constantly remind players auto demolition is a thing once they have a house. If there's an option to disable it, people will. Then they'll still come back and cry how they lost their houses. (Personal responsibility!)