Couple questions/comments:
1- If I did the back side of my cutting mat, I wouldn't have to worry so much about it not coming off when I clean it. The mat I would use stays on my cutting table.
2- Would it adhere the mat to the wooden table?
3- Doesn't spray baste wear off after a couple weeks? So, Eventually it would be gone??
4- I could do a test of a small piece of the fusible, to see how it interacts with the spray baste.
Maybe this idea needs a little more fine tuning (or chucked??). I just am trying to think how to hold a large piece of fabric absolutely in place while cutting.