They are fair, indeed. If I had to answer them, I could only offer my best guess, based on what I've repeatedly read on the Internet: Only devices that have the Google market count. So no, Kindle Fire and forked Chinese Android don't get counted -- not just in the sense "we don't report those numbers", but rather "we don't get these numbers in, we have no idea how much they are, and we don't include them in the 700 000 activations per day".
When you activate an Android device you go through a specific discrete step where you connect to Google's servers and get your account activated. On a side note, I know a lot of people with decent mid-range Android phones, who use them as feature phones and have never registered with Google or activated the device.
That sounds reasonable.
Here's another question: Does Schmidt mean an average per day or simply that on a day or a couple days they hit 700k? This is typically expressed to mean for each day to express rate but without a time frame qualifier it's still fishy. Here's what Jobs said during a previous conference call.
There is nothing ambiguous about Steve Jobs's comments. He's qualified every aspect to refer to the mean average.