No support
1.) It would be hard to verify, as screen shots can be easily faked, so staff/verifier would have to verify the donation via screen share.
2.) We would have no way of knowing if the payment was changed back, if we didn't verify it at a later date via screen share again.
3.) As ABM said, CDT wasn't allowed to host charitable events for some reason.
EDIT: I forgot to add that this would be ultimately a waste of time for sythe from the pragmatic point of view, no matter how honorable the idea is.
If you would like to donate to a charity, you should do so anonymously and don't expect something in return.
1) FAKES: I doubt screen-share should be the method of choice. Who is going to go through the process of convincingly faking an image? I imagine this issue would be a minimal, for what is the consequence of a few sham mini-ranks? This isn't a rank of trust. It's a mini-rank. Also, consider the character of the individual who would tend to desire this mini-rank. I imagine these individuals would be less likely then gen. pop. to act fraudulently. Further, consider the effects of this implementation. I conject a substantial number of individuals would consider donating and explore various charities. A subset of those individuals would donate beyond what they would have otherwise, thereby creating benefit for those in need and fostering altruism.
2) CHARGEBACKS: Would there be charge-backs? Probably very few in proportion to true donations. Do you consider this a substantial issue? Again, would the effects of a few sham mini-ranks be minimal? From what I imagine, yes. Again, consider the character of the individual who tends to act charitably, who wishes to be viewed as charitable (by themselves & others). Even if an individual charged back on the charity (who would do this ...) it would be a charge back of a donation, not a payment. Not a scam (except for the time of the staff).
3) SYTHE CDT/HISTORY: This isn't a reasonable point. Who cares if CDT was or wasn't allowed to host events? Perhaps someone can elucidate WHY they weren't allowed to ... that might be a pertinent reason.
4) ALTRUISM: There is psychological evidence and philosophical reasoning that indicates true or pure altruism is fallacious. Humans are shaped and motivated by a vast amount of stimuli. It's illogical to purport that charitable behavior and donation to charity shouldn't be externally (communally) shaped and motivated, for that principle supports reduced donation to charity. No one donates (or commits any behavior) without getting something in return. People donate because of a cause. It's rewarding to donate for a variety of reasons. Related: look into the concept of effective altruism. Also consider that a number of individuals who would receive this mini-rank already donate

. It's a reminder, and it's encouragement.
5) WASTE OF STAFF TIME: Well, OK. It's up to staff whether or not they care about this. It seems like the screen share method is not the move. Images/e-mail forwards or something more efficient seems better. Is it a waste of staff time? That depends on whether or not the reward (increased charitable/community giving of sythe members) is worth the cost (time of looking at images, googling to see if it's a non-profit org., assigning a mini-rank or whatever). You could also consider a few false mini-ranks a notable cost, but I don't really see it this way. I doubt a flood of people will pour into staff PM's with their charity donations and mini-rank requests.
All in all, the cons are slight in comparison to the pros from what I see.
Support.