I use the same trick by blocking out my whole afternoon every day, and find that it works really well. It turns out that most meetings have no particular time that they need to be scheduled for, so this gives me maker schedule time and makes me far more productive.

One caveat is that if many people in an org start doing this it might become difficult to schedule things, in which case it might be useful for the whole company to coordinate (eg "no meeting Mondays").