I heard back from Juilie -- and also from Erika - both of who really cannot imagine why there would be a problem (mostly because Sage is going to take away the ability to natively integrate any payment provider other than SPS to their products).
Here's Erika's feedback she left on LinkedIn:
Wayne,
To my knowledge, the current agreement between Sage Channel partners and Sage Payment Solutions does require that the partner not offer a competive payment gateway solution nor take compensation from the competitor for doing so.
As you learned at Summit, the future of payment integration with Sage ERP MAS 90 and 200 is with Sage Exchange, the new Sage Payment Solutions tool that streamlines integration between business applications like ERP and e-stores and the Sage Payments Processing Gateway. With the release of Sage ERP MAS 90 and 200 5.0 next year, SPS will be the only payments gateway offered by Sage. We are also going to expand the functionality available to customers using Sage Exchange to include such things as mobile payments integration and more. Our objectives are to make the Sage Exchange/Sage ERP integrated offering so compelling that customers will not only want to use it., but be eager to do so as well.
So if you as a partner are ethically bound to offer what you think is best for the client, we agree that is what you should do. We believe that the SPS solution is in the client's best interest, and are doing everything we can to our future offerings to ensure you and the clients believe it too. Regardless, you are not required to sign the agreement from Sage Payment Solutions in order for your customers to use SPS, you are just precluded from receiving residual payments from Sage in exchange for referring that client to us.