I say this as a long time SCI member...the donation scheme is a sham.
In order for you to set up a table at my chapter of the SCI, you must donate. Typically, you must donate a hunt. Let's call that $5000. Bow every year you come like a good boy and throw my chapter a $5000 hunt for a table for say 5 years and we love you for it. So you decide to go big and do the national event and a different state chapter.
A.) they want a $10,000 hunt, and you do it.
B.) they want it every year
C.) "thanks for the hunt, but there isn't any room left at the convention this year, so no table for you anyway"
D.) Good deeds for local chapter A have no credit given for chapter B or national meeting C
Then you decide to advertise here on AH and your prices suck, because you've been giving away so many hunts that you must charge paying customers more to make up for it and you're not competitive, so you get no bookings.
Then you decide, "that's okay, the auction donation people will buy extra animals or extra days and I'll break even anyway" only to find out that a measurable proportion of those that won auction donations string 2-3 hunts together, kill the minimum game, no tips, then leave. You then grumble in anger that they've taken advantage and no intention of paying for anything.
Inexperience here talking, but I agree. I have heard or read many negative posts/articles about SCI during the past 5 or so years. And I am referring to hunters and outfitters, not antis!
In the end we find you and your friend in the veld with the suicide notes attached after you've given away your life savings to "charities" hoping to build a business and you realize they've taken everything from you and gave little.
So that's how it typically works.
Advertise online and do word of mouth. If some cause has you so enthralled in why they are doing, donate Money instead of hunts for access to advertising.
Just my opinion. Read the online reports of donated hunts by vendors that did so for free advertising or a free table at sci/dsc. A lot of sad stories from all sides.
The pay to play nature of SCI is a horrible thing for the industry.