True, however it's really fascinating that some people are smart enough to discover this group, but not smart enough to use Google for such a trivial question.
No matter what people say, and no matter what websites like this one say, this is an illegal action and people should avoid it. Creating reservations without purchasing a real ticket may be seen as an attempt to bypass immigration rules. Having a real reservation doesn't change the fact that the traveller intentionally wants to exploit the system. This isn't actually difficult to check. It's much better to just buy a cheap bus ticket or something similar.
Nobody knows. It depends on the immigration officer and many other factors. But if it was a visa exemption and you were abroad for only a short time, there's a chance you might not be allowed to enter.