Every lead in your database should have an acquisition program. This video talks about why it's important, and how to set it up in Marketo.
(1:30) The form doesn't have to live in the program itself. The Landing Page is what decides the Program Acquisition, so as long as the Landing Page is a child asset of your program then the form can still live in Design Studio.
It doesn't hurt to have a trigger campaign to set the acquisition program for your more important programs, but landing pages living in a program should do this automatically with any form.
Thanks Joe. I also like to use the {{program.name}} token in the Change Data Value flow step so if I ever clone that campaign, the acquisition step will adjust to where that campaign lives...
but I'd REALLY like to be able to have a global campaign that could manage all acquisitions of off-site form submissions... I've started to scope it out a few times, but can't get all the pieces to connect together -- lost cause for now.