I am not currently a demo, and when I was I don't think this IDA was in effect. However -
here is the Starter Kit order form, and if you scroll down through the pages, it includes the contract.
It says you will not "promote, market, or sell the products" of competitors. To me, if you are on a DT you are promoting and marketing the products of competitors, assuming that you are talking about a company that does stamps or paper or something similar.
Plus like the PP said, the 'blinkie' usually links to a place where ultimately the products are sold.
Keep in mind, in theory if you are selling SU, your goal should be to use products that you can make money on, by inspiring people to make similar projects and buy the supplies from you. I think anything that goes outside of this 'big picture' idea is what SU is trying to limit.