I really see no benefit to donating points within the current system, but should you wish to give them away it's a pretty simple procedure without changing the format of tnbw. Simply post stories with the maximum word and credit levels and tell those you wish to reward to simply paste in a review requiring no effort and grab the points. You don't even have to use real stories, just post a bunch of gibberish or copy and paste something to create the credit potential. Oh, but then anybody could grab the points that way you say; true, but they can grab points that way regardless of any invitation if that is their inclination.
But I do have a question as to why one would want to encourage folks to accept donated points and thereby deprive them of the secondary benefit of reviewing to gain points to publish their own works. Isn't that the whole purpose of the system? You improve your writing by reviewing and your writing improves hopefully by being reviewed. The two work hand in hand. As it is, you must review about four works of equal length to the one you publish to gain the points to publish; a sensible ratio it seems to create reviews for a broad spectrum and still make it quite easy to gain the points to publish.
It is obviously quite easy to gain points to publish and create an excess or else all these points wouldn't be available to donate or sell as the case might be. Yes, it does take time to do the reviews, but not nearly as much time as it takes to create the story to publish and it seems logical that giving away free points would diminish the total pool of reviewers for that greater effort. I mean why review if you get the points for free even if for past efforts. Giving away points lessens the value of the reviewer as well as the incentive of the reviewer in my opinion. The more appropriate response to reward a good reviewer would be to give them more reviews than you receive since that is the ultimate goal of authors on this site, to get reviews to improve their work.
Well, that's my free points. And yes, I have more than I'll probably ever use also, but wouldn't want to deprive others of the education and relationships from whence they came. Take care. Vern