Jim Harbaugh may have been the first to decide to hold spring practices at the IMG Academy. Unless the NCAA makes a rule prohibiting the practice, he might not be the last, as Ohio State head coach Urban Meyer brought up the possibility of the Buckeyes doing the same thing in 2017.
Michigan received a lot of press for their practices this year at IMG Academy, along with a lot of exposure to recruits in the South. If the process works, and NCAA does not ban the practice, then other schools should follow them in taking advantage of this process.
Of course, I expect the SEC will have something to say about these practices to the NCAA rules committee, so it will be entertaining to see how long this lasts and how many schools are able to take advantage.