1) It is funny you say this, because that is how most platforms are. Look at Apple, Twitter or Microsoft. Not to say your warning isn't justified, but it is part of the game that is played when dealing with 3rd party platforms. They introduce them to bolster their own networks, and if they don't like what you are doing, or feel that you are competition, they will force you out one way or another.
To be fair, some of these APIs expose data sets and user bases that we couldn't have dreamed of accessing ten years ago. It sucks when we get locked out by the API provider, but the availability of these APIs has transformed what a single developer or small team can create.
