Is it possible to stake tokens for an app's bandwidth on behalf of the app owner if you yourself are not the app owner? This could be for applications like charity or leasing, for example.
I think the answer is "yes". Dan says so in the video: https://www.youtube.com/watch?v=N6CTRdx6NVE
And if you read the code for the system contract, it has two arguments for staking and unstaking:
receiver, which can be different. In addition, you can lock out the receiver from unstaking.